Incorrect battery fitted to vehicle

Battery Centre agent in Potchefstroon (Hi-Tech Autolec) fitted the wrong battery in my daughters vehicle. They advised her to fit a 652c battery that is a 66Ah battery in a 2007 BMW 325i (E90) that is actually supposed to be fitted with 90Ah battery. This reduced the life of the battery and caused multiple problems with the vehicle. They refuse to take any accountability for this. I contacted First National Battery who owns the Battery Centre franchise and they also rejected my claim.