terrible expirience with Budget insurance third party claim

terrible 3rd party assistance I was involved in an accident with one their clients on 25th NOVEMBER 2018 whereby their client accepted liability for causing the accident . Budget has taken it's time processing the claim as well as updating me on what documents they need to process third party claim, only after I called after a month towards end of December enquire when are they going to start processing my claim that's when I was told I must take my vehicle for inspection to their assessor .I explained to them that the mode of transport I use everyday to and fro work is my vehicle as I live far from accessing public transport therefore I couldn't wait for them as my work also doesn't promote use of public transport and decided to take my vehicle for repairs and keep the record, I explained to them that I obtained three quotations and re**** on the less expensive one, they were happy with what I did even explained I did the right thing by comparing the quotations, I sent them all the relevant documentations and photo's to confirm damages on my vehicle which Now I am told that they can only settle repairs done on my vehicle with half of what I spent which I believe is unfair, I asked them a simple question of was I supposed the whole for them to repair my car for something wrong that was done by their client whereby now they are telling me they are prepared to make an offer which is tantamount to 60% of apportionment of the work that was done on my vehicle. A very bad experience with Budget with regard to third party claim, I've requested them to review their offer as I'm not happy and is not what we agreed upon !!