Pathetic service from dealership to head office

Took my car in for a annual service on a Friday and asked that they check my battery as it had given me trouble starting the same week. On collection was told that car did require new battery but the one they had in stock had a default with it and I should come back on Monday to have a new one fitted. Confirmed that I would come first thing Monday morning with the sales consultant, Minette which she confirmed. Arrived on Monday and battery was not available -told they would call me when they had sourced -would be that week. <br> <br> Called a week later, spoke to Minette again who said it would be available the next day. She has obviously only heard about \over promising