You have a cause of action in breach of contract and/or the tort of deceit (i.e. fraud and theft) against the fraudsters for eliciting monies from you by deception.
If your expected damages are under £10,000 and you do not make an express pleading of “Fraud”, you may issue court proceedings via the Government’s Small Claims Track Online System: https://www.gov.uk/make-money-claim. The issue fee will be no more than £410.00. A party cannot normally recover solicitors’ costs on the Small Claims Track. However, it is designed for non-lawyers (known as “Litigants In Person”). The trials are relatively informal, and the judges do not expect parties to have the same legal knowledge as experienced solicitors and barristers.
However, if your expected damages are between £10,000 and £25,000, the claim will be allocated to the Fast Track, and if damages are over £25,000, it will be allocated to the Multi Track.
If you plead Fraud on the Claim Form and Particulars of Claim, the Claim will automatically be allocated to the Multi Track regardless of its damages value.
The Fast Track and the Multi Track are much more formal and legally technical, and it is expected that both parties will instruct solicitors. The normal rule on the Fast and Multi Tracks is that the winning party (either at a Final Hearing, or through a negotiated settlement) can expect to receive most of their legal costs from the losing party.
If you make a pleading of Fraud and lose at Trial, you will have to pay the Defendants’ costs on the “Indemnity Basis” which means that you will essentially pay their Bill of Costs in full as served and filed without it being assessed by the Court for reasonableness and proportionality.
If your claim is worth over £10,000 and/or you are minded to plead Fraud in the Claim, I strongly recommend that you instruct specialist solicitors who are experts in commercial dispute resolution, financial crime and court litigation to advise you and conduct the litigation. If you cannot afford legal costs upfront, you should contact your home or business insurers and ask if they will cover your legal costs under a legal expenses insurance policy. They will either pay your solicitors’ fees or appoint a law firm on their panel of solicitors to act for you.
However, the potential defendants may be difficult to trace and may have moved your money to several other bank accounts outside of Western legal jurisdictions. I recommend that you report this matter to the UK Police’s online financial crime unit, Action Fraud, who may be able to assist: https://www.actionfraud.police.uk/. If Action Fraud are unable to trace the other parties, you must instruct your own financial crime investigators at your own cost.