Viking Client Services, Inc. Debt Collection Complaint

Viking Client Services, Inc. Debt collection department,

Other (i.e. phone, health club, etc.) Cont'd attempts collect debt not owed Debt is not mine California

I rented a car from -. When I arrived they did not have the intermediate size car I had reserved and prepaid at a rate of $73.00 and could only provide a larger car which would be more expensive. They quoted me an additional $56.00 for the rental. I was not very happy about that but had few options so I accepted. When I returned the car at the time agreed, they instead charged me an additional $150.00 with no explanation or justification for the increase. I repeatedly phoned the - office who said they would adjust the charges, but they did not. Finally I disputed the additional charges with my credit card company. During this process - had an opportunity to contest the dispute and they did not ( as seen in the letters from -. ) Therefore - refunded me the $100.00 that was over and above the amount I agreed to pay. I thought this was the end of it until I received a debt collection letter from Viking. Now, this is affecting my credit and I do n't know what to do. I *do not owe this money* - but there seems to be nowhere I can go to establish this fact.