Third party unpaid claim and I am harassed and threatened with legal action

I have been a client of Miway since July 2010!!!!!!!!! and I have had several claims which were ALL paid out and settled, except for one. My last write off incident happened in February 2017 and Miway paid out my claim and I continue to be a loyal client, just last week I added my laptop in my insurance cover, I did this online! So revolutionary!!!. With all these positives milestones registered since I have been a client, there seems to be a dispute between Miway and the third party (Avis car) concerning this particular 2017 write off incidence. This dispute is starting to affect me and my wife's life. I am being constantly harassed by Avis who allege Miway has not paid for my third party costs (damage to their car) and they have threatened me with legal action!!!! I don't see why I should be subjected to such after being so loyal to Miway, it is unfair. Please sort this nonsense out with the third party