I think your accounts will have been closed, so don't send money to them as it could well end up getting lost in the system.
Bangkok Bank were pretty good when I contacted them about an issue I had whilst I was in the UK. Try contacting them https://www.bangkokbank.com/en/Contact-Us
As far as a residency permit is concerned, I'm not sure what that is to be honest. Do you mean a certificate of residence? Most immigration offices would require you to be on an extension issued by them in order to get one (although some may issue it to you). You can, if you're on a Non-Imm type visa get an affirmation of residence from the British Embassy in Bangkok
Here's their guide https://assets.publishing.service.go..._residency.pdf