No ethics

I recently did a deal with this company and after agreeing to the terms with their representative and meeting with one of the company people when it came to concluding the deal they turned on the deal and wanted a substantial amount more for the product than originally agreed upon. I wrote to them to complain and they have ignored all correspondence bar to say that they had made a change to the product and wanted more and suddenly in the last 3 days had major work for it. Clearly a company run by ************ leaders with no ethical principal