Synchrony Bank Debt Collection Complaint

Synchrony Bank Debt collection department,

Other (i.e. phone, health club, etc.) Cont'd attempts collect debt not owed Debt was paid California

I paid off the amazon store card in full and closed the account. Apparently a refund arrived on the card at some point and I am owed some amount of money. The collection company seems to think that because the balance is not - I owe them something and they call 5 times a day. However, if I actually talk to them they realize after wasting 10 minutes of my time that they owe the money to me! While they promise to send me a check and correct the account, this never happens. And an hour or two later they will call again! This has gone on for weeks. SynchronyBank, via Amazon Store Card program.