Well did you actually exchange the purse or not? Forget camera footage -there would be a transaction slip/record for this exchange, and not just the LP's testimony.
It's not completely clear what the exact charge is from your post. Is it just the purse exchange? What I got was you also had a shopping bag(s) full of merchandise purchased previously from their store with no receipts and you were walking around in the store, shopping, scanning items, etc. Is this stuff involved as well?

