2x Deposit on same hired vehicle which was extended.

Debiting my card twice for 2x deposit on the same vehicle without my consent. I rented a vehicle via my insurance, but as usual the insurance took longer than expected to finish the car as this was holiday season, so I had to extend my rental with additional days but after 30x days, AVIS debited my account again, didn't have enough there as I was not expecting any debits, now this put my bank account on negative and now I had to sort that out and AVIS is busy demanding another deposit, I told them I will not pay for what they should've communicated with me the first time I extended rental. Now they don't want to rent a vehicle to me cause they want me to settle first. T