promises for payment

My daughter took her car for a 30000km service in October 2014. During the service the break pads had to be replaced which was not done. She had to replace the break pads lately. We had a discussion with the service manager where he admitted that it was their fault. He asked for the invoice for the break pads she replaced out of her own pocket and promised that she will be refunded within a week. It is now close to 3 weeks and still no refund. I went to the garage this morning to find out what the status is and according to the financial lady working there she is not aware of such a payment. She also was not very helpfull. The service clerk asked for our details which my daugter sent them again this morning.