Thanks for the insights.

Two questions

1) Bitcoin needs time to transfer. How did you approve the transaction? Instantly in hoping it will go through or had the costumer to wait?

2) The problem with new Stellar addresses is, that they need to be "funded". Your sending wallet has to recognize if this address is empty to run the right function (it's not a normal transaction). Most of the wallets can't do that. They wouldn't be able to transfer any funds. Have you had problems with that?