Diagnosis: eBay overselling
- Store
- Fernhill Supply Co. (fictional)
- Channel
- eBay via Shopify Marketplace Connect
- Records compared
- 100 SKUs
- Delivered
- 1 business day after materials · free
- Fix tier
- Small fix ($50) clears F-01; fix ($150) covers F-01 to F-03
§1 Summary
Reported problem. Between 2 and 15 October the store received 7 eBay orders for items that were out of stock in Shopify. Each one had to be cancelled, which cost refunds, a defect on the seller account and roughly $410 in fees and lost margin.
- 100SKUs compared
- 14Mismatches
- 9 / 14Explained by one setting
- 7 / 7Oversold orders explained
We compared 100 SKUs across the Shopify inventory export, the Marketplace Connect listing export and the eBay active listings report. 86 matched. 14 did not.
9 of the 14 come from one setting: eBay quantities include stock held at the "Returns shelf" location, which the store does not sell from. This explains all 7 oversold orders.
3 are listings with a fixed quantity override, 1 is a variant that was never linked, and 1 we could not explain from the materials provided.
§2 Mismatches
All 14 records where Shopify and eBay disagree. The other 86 matched and are listed in the attached spreadsheet.
| SKU | Product | Shopify available | eBay quantity | Diff | Finding |
|---|---|---|---|---|---|
| FH-1187-BLK | Trail bottle 750 ml, black | 0 | 3 | +3 | F-01 |
| FH-1187-GRN | Trail bottle 750 ml, green | 2 | 4 | +2 | F-01 |
| FH-1302 | Camp mug, enamel | 0 | 2 | +2 | F-01 |
| FH-1415-M | Fleece beanie, M | 1 | 2 | +1 | F-01 |
| FH-1415-L | Fleece beanie, L | 0 | 1 | +1 | F-01 |
| FH-1520 | Dry bag 20 L | 4 | 6 | +2 | F-01 |
| FH-1633 | Headlamp 300 lm | 0 | 1 | +1 | F-01 |
| FH-1701 | Paracord 30 m | 3 | 5 | +2 | F-01 |
| FH-1788 | Sit pad, foam | 0 | 2 | +2 | F-01 |
| FH-2210 | Trekking pole pair | 6 | 10 | +4 | F-02 |
| FH-2244 | Stove windscreen | 1 | 10 | +9 | F-02 |
| FH-2290 | Tent footprint 2P | 0 | 10 | +10 | F-02 |
| FH-2315-XL | Rain shell, XL | 5 | 0 | -5 | F-03 |
| FH-2402 | Map case | 2 | 0 | -2 | F-04 |
§3 Findings
- F-01
eBay stock includes the "Returns shelf" location
Confirmed9 SKUs, all 7 oversold orders
Shopify has two locations: Main warehouse and Returns shelf. Online sales only use Main warehouse, but Marketplace Connect is set to sync stock from all locations. Items waiting for inspection on the Returns shelf are therefore offered on eBay. For each of the 9 SKUs the eBay quantity equals Main warehouse plus Returns shelf, exactly.
Evidence: Inventory export rows 12–40 (per-location columns); Marketplace Connect settings screenshot S-02; order list screenshot S-05.
- F-02
Three listings have a fixed quantity of 10
Likely3 SKUs
These listings show exactly 10 on eBay regardless of Shopify stock, which is what a fixed-quantity override on the listing produces. The listing export marks them as overridden, but we have no screenshot of the listing settings themselves.
Evidence: Listing export column "Quantity rule" rows 58, 61, 77.
- F-03
One variant was never linked
Confirmed1 SKU
The XL variant of the rain shell was added in Shopify after the eBay listing was created. It has no eBay variation, so eBay shows 0 and buyers cannot choose it.
Evidence: Listing export row 83 lists S, M and L only; Shopify export row 91 includes XL.
- F-04
Map case shows 0 on eBay for an unknown reason
Unknown1 SKU
Shopify has 2 available, the listing is linked and has no override, yet eBay shows 0. The materials do not show why. The Marketplace Connect sync log for this listing would settle it.
Evidence: Listing export row 88; no log provided.
§4 What to do next, in order
- Sync stock from Main warehouse only
In Marketplace Connect, set the inventory locations for eBay to Main warehouse. Expected to clear 9 of the 14 mismatches and stop the overselling. Check the 9 SKUs again after the next sync.
- Remove the fixed quantity on three listings
Open FH-2210, FH-2244 and FH-2290 in Marketplace Connect and switch quantity back to "Use Shopify inventory". Confirm the setting first; this finding is likely, not confirmed.
- Add the XL variant to the eBay listing
Publish the missing variation from Marketplace Connect rather than creating a new listing, so the existing listing keeps its history.
- Ask Shopify support for the Map case sync log
Send them listing FH-2402 and the time window. If the log shows an eBay-side rejection, the error message will name the missing field.
§5 Limits of this diagnosis
- We worked only from the exports and screenshots provided. We did not log in to Shopify, Marketplace Connect or eBay.
- The sample covers 100 of about 640 active SKUs. Other SKUs held on the Returns shelf are likely affected by F-01 in the same way, but we have not checked them.
- Fees and lost margin are estimated from the order screenshots, not from payout records.
Materials received
- Shopify inventory export with per-location quantities (CSV, 100 rows used)
- Marketplace Connect listing export for eBay (CSV)
- eBay active listings report (CSV)
- 6 screenshots: channel settings, location settings, 4 cancelled orders