Quote from: nc50lc on Today at 03:27:58 AM

Quote from: Surmount on Today at 12:31:59 AM

EDIT. Found the address. Apparently Shakepay sometimes changes the address, maybe after every transaction.

You must be talking about your Shakepay deposit bitcoin address.
They do change deposit address but if it work just like any exchange, the address used for withdrawal isn't tied with your account.
It could be one of their "hot wallet" address that's specifically used for users' withdrawals (can't be 100% sure without the address).

Quote from: Surmount on Today at 12:31:59 AM

Forex has very strict AML policies. Cash can only be withdrawn to the same source that made the deposit. They've specifically told me that they can only withdraw to the same BTC address that made the deposit.

If it's AML policy, try to explain to them that you've bought bitcoins through Shakepay (a custodial service) and sent the bitcoins to them.
Sending them your transaction history might help. (Link: help.shakepay.com - Where can I see my full transaction history on Shakepay?)
You can also send this thread's link as a reference.

There should be a qualified technical support that can understand that Exchange withdrawals doesn't work like a non-custodial bitcoin wallet.

You mean an address previously used for my account may eventually be used for someone else?

After digging I found that on June 25 I had made a successful withdrawal from the forex broker to a BTC address. On Shakepay I see I received BTC on June 25th and cashed it out. The amount I withdrew and cashed out is nearly identical. Blockstream also shows that it was sent to the address that the forex broker wants me to use.

Coinbase say they change the address but the old ones remain tied to the account. Must be the same for Shakepay.

For now I've withdrawn a small amount from the forex broker to the specified address. Will wait and see if it ends up in my Shakepay account.