Excess Fee on claim.

I logged a claim for an accident on which i was involved in and i was provided with the information on which the car needs to be taken in for assessment. Quote was done and sent through to insurance company and then on the 19-10-2017 i called in on the claims department i was told that i would need to pay a 20% more on the excess fee on which on which on the contract it stipulated that a 10% of the claim amount on top of the excess fee needs to be paid. Currently i'm not happy with the insurance as i have been a loyal client to them and they giving me all the ammunition to move to a different insurance company.