We do not withhold clients' funds: we either exchange them or, in exceptional cases, make a return to the address from which the funds came to us.
This is in contrast with using your own stock of xmr is the exchange done via exchanges APIs or you are directly selling your new bitcoins?
Since you mentioned the possibility of a "refund" does this mean that there are conditions of use or use of AML bot or the possibility of requesting user data?
Why don't you have an onion page that would have higher privacy than using a Telegram bot.