888 Casino - Verification and withdrawal timescale

Opened account on 9th Feb, deposited via Trustly from a joint account, played and won £8500 asked for withdraw and on the 10th Feb account limited and been accused of using a 3rd party account.
Asked to send Id so I did plus bank statements and screenshots proving it was my account.
Still waiting for verification and contacted them via live chat and email to be told they are busy and that it's been escalated but still no winnings.
I've also been told that it was 72 hours, 3 days now it's gone to 21 days to get verified.
I find this unacceptable I think in future you should verify customers before being allowed to deposit as this is really frustrating the fact that people win but can't get their winnings when they've played with a big company like yourselves and putting their trust in you.
I had made plans to treat family with the winnings but have had to cancel all my plans.
I am losing faith in the fact I will ever see my winnings. I've never ever dealt with a gambling company like this, on other sites 24 hrs to verify and receive winnings.
I hope we can get this resolved asap and hopefully you will look into a easier quicker way to verify customers in the future.