Waiting for my refund from August!

I bought a ML63AMG from webuycars in August this year. There was some work that needed to be done before I took delivery of the vehicle. When I collected the vehicle there was still an outstanding item that the workshop they took the vehicle to do the repairs was still waiting for the part (new tail light). When the part finally arrived iy was the wrong part. They then came back and said that the correct part is quite a bit more expensive and they are talking to webuycars to see who is going to pay for the difference. After another month of back and forth I asked them to just refund me the money and I'll sort out the tail light on my side. That was on the 17th of November. Nothing. On 2 December I logged a formal complaint with webuycars via their website REF NO 33010. They only contacted me on the 8th of December, asking for detail and a copy of the quote. I sent that through the same day. From there, again nothing. No feedback, no answers to my emails, nothing. CAN I PLEASE JUST GET MY MONEY BACK!