Recently talking with someone and they told me a interesting story.
This person made an online purchase from a very large online retailer for a single item (worth about 80 dollars)
What they received was a case of ten of that item (worth about 800 dollars)
The item is useful to them.
Would you keep the extra 9 pcs or contact the online retailer to return them?
I know what they did, I know what I would do, but I thought it would be interesting to gauge responses.
I know someone that ordered a dining room table on line, ~$2500.
When it arrived and was unpacked it was the wrong design. She advised the supplier and was told she had to re-order and would get a full credit upon the return. This makes sense from the supplier's end because it means they don't have to chase the client to get the wrong one back.
She does as requested and she gets the right model but wrong colour. Repeat
The third one comes in as ordered but with a scratched top. Repeat.
Finally she got what she wanted but upon going over her purchases and credits they've over credited her. They actually have paid her to take the table. She has spent hours trying to explain the math. They say no, the account is clear. OK she says, call me if you find out otherwise.
As others have stated the excess is not legally yours and no different than a bank error making your account look fatter than it really is.
However it is only your job to advise the other party. It's up to them to correct the error. They decide what they want to do. One should expect a certain amount of inconvenience but that is part of ethics and it doesn't mean you have to safely store the product for unreasonable lengths of time.
I got home one day to find several skids of jiffy mix concrete on my driveway the result of a similarly named street nearby. I called the company and advised them of the problem and my need to get into my garage, suggesting if the problem wasn't resolved in three hours I would put a "FREE" sign on the lot. It worked.
How much to worry about? A hundred dollars doesn't buy a lot of office time chasing paper but larger amounts could pop up down the road. If the item got used or depleted you could get a bill. You could theoretically charge storage but now we get into expensive legalities.
If the first phone call doesn't resolve anything switch to emails for a communications track.
If the item is large storage could be a problem. Ship the excess stuff back collect or if the product is a regular purchase send them $XX every time you use another item. Take a discount for a volume purchase and charge for storage. I don't think any accounting system could handle that and you might get a call from a human being to resolve the issue.
The legal and ethical answer is to make a phone call and put the ball in their court. Common sense would determine time lines.
