Verification issue and not withdrawing funds, can't understand

I have had issues trying to withdraw my funds, they keep on telling me I need to upload different documents which I keep on doing even though my account states it’s verified on the verification page. I have had multiple live chats with them and also emails which are attached, it is a lot of money that I have deposited (£3000) and I won £3744 which I would like in my bank account, on the last email received it stated if the correct information isn’t submitted they will close my account. I first tried to withdraw £139 which they said my bank cancelled the request even though my bank didn’t, I then tried to withdraw a bigger amount and this is where I am currently.. No answers from them and every time I go on live chat they say more documents are needed but they don’t contact me to tell me this.