Frustrated client

I joined liquid capital in 2017,have been servicing my car with them till 25 August this year. They were supposed to pay for belt replacement but they declined it saying that it was supposed to be replaced at 4 yrs or 90000km,but using the one that comes first. According to the agreement it says if the OEM recommends the replacement then it should be done.They put the blame on Renault Woodmead,saying that they were supposed to replace it then. I called them several times trying to show them this but they didn't budge. I asked for the call recording till today I have not received it.

I decided to cancel the contract and asked them if there will be any levies, they said no. Today they sending an email saying I need to pay for a shortfall.

I no longer know what to do in this situation.