qte me wrong /bad service costly on repairs

I went to bosch in wilropark for my car service. i asked them what will it cost. they gave me a quote of R2700 for a major service on my car. took the car in for service asked for the co2 cost price they said R350 to do the co2 levels for me. i told them to do it. so it works out to R3050. she phoned to say the quote is R3900 because i need to fit my filters so my cost is R3900. I SAID FINE. I GOT TO THEIR OFFICE TO COME FIND OUT I HAD TO PAY R4054 for my service. they never did co2 levels. and i paid so much for thinhs i don't even know about. i even phoned my aitime finish which they had to phone me to tell me what is going. i just feel they really have attidut problems and they don't know what custemers service is. i am really not happy with this service.