Tonerbuyer.com review: Compensation

Sold 9 used cartridges to Tonerbuyer.com. Packed tight with several filled air pocket packs to protect shipping. Completed packing slip and shipped off via UPS. Rec'd check for $6.00, which was 1/3 of what we should have received. Payment was sent within 21 days. Called company to inquire about payment (check should have been for $18.00), and was told that "two had broken in shipping" and that because there was a minimum of 8 cartridges required, that payment had been further reduced to cover shipping. Sounds like a scam to me. I will never do business with this company again. I will use Staples or Office Max in the future.