Wort company to deal with

This company purchased a product from us, our specification was incorrect, they logged an RMA after opening and using the product, they refused to let us collect it for credit and continued to complain without specifying how they wanted us to assist. Tried calling but their phone number 021 529 7300 and cannot get through the menu selection as it does not register inputs and just keeps looping. So, I tried calling the account manager number in the CPT branch and he answered, then dropped the call in my ear not 10 seconds into the call. No return call nothing. These people are ridiculous.