Thanks, ***** ***** have to give you the news....
I have checked and that trading company is not regulated according to the Financial Conduct Authority (the FCA).
Therefore I am almost certain this is a scam and they have just taken your money.
The first thing to do is to report this to the Police and to Action Fraud so that you can obtain a crime reference number. The Action Fraud website where you can report the crime is here: http://https://www.actionfraud.police.uk
Once you have done that then see if your bank or credit card company can do a charge-back on the monies as a lot of these trading companies are not legitimate outfits. If you paid with a credit card you may be able to make a claim against the card provider under Section 75 of the Consumer Credit Act. If you paid by debit card then your bank may be subscribed to the voluntary code to refund you if you have been scammed. The bank can charge-back up to 120 days from the date you sent money or paid money to a scammer.
In future my advice is to check whether the trading company is FCA-regulated first of all to ensure they are legitimate. You can check here : https://register.fca.org.uk
The FCA website has a list of regulated companies so this would be worth checking.
If there is no record, I would urge caution and do not give them your personal details, nor any money. The reason being if they are unregulated, there is nothing the FCA can do and in all likelihood the company is based abroad so suing them would be difficult if you wanted your money back. Most of these companies also ask for the initial £250 up front and tempt you to add more funds only for them to become non-responsive when you ask to withdraw.
There are a few companies who can claim to retrieve monies taken by a scammer but in reality they are also scams - once a scammer has the money it would be very difficult to sue them (being based abroad) and even if you obtained a CCJ against them, enforcing it is another matter.
You can try https://www.selachii.com/advice-for-victims-of-bitcoin-fraud.html to see if they can help but insist on a no win no fee agreement with them and do not pay anything up front to them. At least that one is a regulated law firm in the UK.
I hope this helps - if you can please accept the answer and give me a 5 star rating (there should be a button at the top of your screen to do this), I can answer follow up Q&A's at no extra charge and Just Answer will credit me for helping you today.