Mendoza Lawn Care

I was paying the invoices that I was receiving in the mail I realized in the last month that I had overpaid b/c the statements did not list the payment amount and I did not notice that the mailing address had changed on the statement
I called *** and confirmed that she got the payments and she said I had a $credit I asked for her to send me a refund I have called times and she has said that she has mailed it
Meanwhile, I have not received a refund but I continue to get bills in the mail
When I called to today to ask what was going on she hung on me? I was in my car and couldn't tell if she could hear me She remarked that I was yelling at her and hung up and would not pickup the phone after that