Rip off

Deposited money on Mr green. But I had self excluded myself from sister company. So they excluded me from there. I asked can you refund my deposit then. Which they said I had to show them last 4 digits of my 16 number on bank statement. I keep on explaining on bank statements they do not give you the 16 digits all they give you is sort code and acount number. Which they have seen when I sent them bank statement showing transaction. They keep saying go to live chat but when I do they say it's not enough evidence. All they need to do is refund me to same acount I used belonging to me which is registered to my address. They are ripping me off. Beware dont use them