Santos Dumpster

I rented a 30 yard dumpster to dispose of old kitchen cabinets and years of junk and debris that had accumulated in my rental property. They quoted the price of $600 dollars and an allowance of 3 tons with each additional ton being an extra charge. I filled the dumpster up and called to have it picked up. The dumpster sat in my driveway for 2 weeks until they picked it up. A few days after they picked it up, a charge of $545 appeared on my card on top of the $600 initially paid. I called to ask about the charge and they informed me that I had loaded an additional 3.4 tons into the dumpster, which is absurd. There's absolutely no way the debris that I tossed in there amounted to 12,000+ lbs. When I called to ask to see the weight tag from the dump, they sent me a weight tag from a drive-through scale and said the dumpster was still loaded in their yard. How can you charge for the weight of the load if the empty truck was not weighed after dumping the load? I spoke to the manager and he said they would credit the card until they dump the load and get the real ticket, but after calling every day and getting the runaround, they stopped answering.