Bad Service

My car was taken in for repairs as it had indicated that the coolant level is low. It was at BMW Auto Glen for 3 days the next day that warning light came back on again and I had to take my car back today. I advised the consultant that I would need a car as I cant carry on like this and she advised that they had no pool cars however a car from a car hire company has been arranged and she did not advise me that I would have to pay for that car. the car hire company just called me and advised me of that. I am very upset I didn't expect this from BMW especially because I take my car there all the time. this is totally bad service and that shows that my car was not fixed properly.