Thank you very much for clarifying. First of all, I am sorry to hear about the issues you have experienced in your situation.
Whilst you can request that, no one can force them to finish the job so if they refuse to do so you would be left with only seeking compensation from them for any losses or extra costs incurred as a result of heir work.
If a party wishes to pursue another for financial compensation arising out of a dispute between them, they can potentially do so by making a court claim. However, as legal action should only be used as a last resort, there are certain steps that should be taken initially to try and resolve this matter informally and without the need to involve the courts. It is therefore recommended that the following steps are taken in order to try and resolve this:
1. Reminder letter – if no informal reminders have been sent yet, one should be sent first to allow the other party to voluntarily settle this matter.
2. Letter before action – if informal reminders have been sent but have been ignored, the other party must be sent a formal ‘letter before action’ asking them to resolve this amicably within a specified period of time – 14 days is reasonable. They should be advised that if they fail to make contact to resolve this matter, formal legal proceedings will be commenced to pursue them for compensation. This letter serves as a ‘final warning’ and gives the other side the opportunity to resolve this without the need for legal action. There are numerous templates available online for such letters and a simple search will bring up a list of useful results.
3. If the letter before action is also ignored, formal legal proceedings can be initiated. A claim can be commenced online by going to https://www.moneyclaim.gov.uk/web/mcol/welcome. There will be a fee payable, which depends on the amount that is claimed. The other side will eventually get a copy of the claim and they will have a limited time to answer it. They could accept it and pay what is owed, they could accept it only in part and defend the rest, or they could outright reject it. They could also completely ignore it, in which case judgment will eventually be entered automatically against them. Also, it is worth noting that the simple act of submitting a claim could show the other side that this is being taken seriously and prompt them to consider negotiating a potential solution to stop the claim progressing further, such as offering full or partial payment of the amount sought in the claim.