Worst service Ever, poor attempt to resolve an issue

I recently put a claim for a windscreen, I took pictures, PMD required, after a few days PMD sent me a quote that directed me to PG glass in East London Vincent Park, after they had finished, I paid the excess I was quoted to pay,I was surprised by the new amount I'd have to pay, in the communications PMD sent and my recordings they sent, they kept on referring to 25% excess that I had agreed to pay, of which I've paid the excess amount that was quoted to me by YOU.I received a poor attempt of a resolution, which also refffered me to excess that I had agreed to pay, And a pathetic excuse that :"its not in your control that the service provider changes the prices", who's control is it? At who's inconvenience? Kindly fix this mess and please refund me my money that I've paid, not the excess that was quoted in this attachment but the unexpected difference that I was pressured to pay by both your people and PG glass.