Money transfer from VN to my bank account in UK (Ho Chi Minh City)

Hello!
I now live in Saigon and I need to transfer money to my HSBC bank account in the UK.
HSBC in Saigon has refused to take my cash in order to drop it into my HSBC bank account in UK. They said they did not provide this service.
Techcombank said they did not accept international transfer.
It seems to be a bit complicated and I did not find any solution so far!
Do you know any way to do this?
Thanks in advance for your help!