No reply after requesting invoices

I called today to request some invoices due to a dispute in a house we rented for three years. I was told by the lady that she doubts they can supply me with invoices so far back, but she would ask someone there and they would get back to me. Guess what, I'm still waiting for them. This isn't the first time i have had a problem with drain surgeon. The previous time had to do with not receiving the discount as i was paying cash, and i had been told u get discount for settling immediately by making a cash payment. When querying that, admin just never got back to me. I let that slide, but why should i just let it go now. This is a matter of urgency and i need those ASAP. If a person cant even receive copies of those, why even make use of their other services.