Premier Service (Independent Mercedes Benz Centre) in Leicester

Don't know how many times I have been done over by this company. Thought I could trust them. Naive or what! Recent experiences: gave a list of problems I wanted resolving with my merc. They did a B Service. Failed to change the indicator stalk on that visit. Failed to sort out my srs light on that visit. Failed to sort out my electric seat on that visit. Booked me in for another day and phoned me cancel or reschedule the booking. Arranged another day and yes you guessed they phoned me to reschedule again! On this visit they changed the indicator stalk and sorted out srs light but no success with the seat. Booked me in again and still no success they decided it wasn't the wiring or the switch as they had said but it was the seat motor. I asked them to quote me on seat motor and they said £310. I contacted main dealer and was quoted £188. 40 by main dealer. Guess who I chose! So if that is any indication of what has been happening to me check before you use this company. I feel I have been had over good and proper. They are more expensive than a main dealership. The work this company did carry out was at a cost of £900. Is that reasonable?