Witholding credits!!!

I was in an accident late Aug 2018, after 3 weeks Virgin via AIG made a decision to write off my car, i had no choice and went with their decision. At the time of the write off my premium had just gone my account, when i queried it, Mumtaz at Virgin said i would get a credit when i added my new vehicle. I eventually found a car I wanted and when i requested a quote from Virgin, the premium was sky high and my excess had been changed apparently as the write off affected my profile, regardless that it was not my fault and we have witnesses to that effect. I declined their quote and went elsewhere for new cover, now i am trying to get my refund of the credit on my account and no one wants to help me, i get told they will call me back and no one does, its been over a week now and nothing. I am appalled at the service and very disappointed. I want my refund.