No care for customers

So I serviced my car out of my own pocket, not aware that I still had active service plan. When Lindsay Saker Kempton Park had to pay me a refund after AVIS paid the claim, they paid less than half of a normal service fee they charge without extras. I have been waiting over a month now for this refund. They do not take care in responding to my emails until I call them. This time, my email is with accounts department over a week, no response. Very disappointed that they can not resolve simple queries like this.