It appears that the supplier may have breached their supply of services contract with you. The supplier is under a duty in contract law and statute to provide you with a product and service that is fit for purpose, of reasonably satisfactory quality and matched the description at the point of sale. Your damages will be a refund on the price paid for the period when their services were not up to standard, plus additional costs of rectifying their defective work through another supplier.
Damages for breach of contract will be the other party’s payments for the remainder of the fixed term, or the notice period for termination of the contract. You must present the defendant with a civil claim and issue court proceedings in the County Court.
If your expected damages are under £10,000, 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. These tracks 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 your claim is worth over £10,000, I strongly recommend that you instruct specialist commercial dispute resolution and court litigation solicitors 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.