Crypto Trading Platform

Hi, I was wondering if anyone has heard of the crypto trading platform known as Rcoin. Here's the link: Rocincbm.com

I have been using them for the past couple of months to great results. However, as of my last time trading on the platform, I had reached over 100k in USDT, whereupon they froze my account from making withdrawals, requiring that I pay them for a large fund management fee using funds from an external source. I had asked them multiple times as to whether I can make the payment from my account with them but they've said multiple times that it is not possible and I am starting to think it's a scam. This has caused issues with me and my bank as they have taken the stance that this is a definite scam and blocked my accounts with them (I live in the UK). Any advice on how to proceed would be greatly appreciated.