Worst customer experience of my life - treated like a ***** and threatened with legal action by this unprofessional business

Absolute worst customer experience of my life. When I recently decided to have a deck built, I chose HM Creations as they did a previous job for me installing floating shelves in which case I was satisfied with both the service and product. However, the installation of my deck was an absolute nightmare from the start. I was quoted R1400 per square meter using massaranduba. After paying a 60% deposit, Ryan informed me that he could not find suitable wood and suggested that we use gum instead. As I was not fami**** with the use of gum in decking, Ryan verbally assured me that the R200 saving per square meter would make it worth my while. As the size of my deck was 32 square meters, this meant a R6400 saving. Despite my request for an updated invoice, I never received one reflecting this change. The job itself ran over by more than a week and deadlines were simply disregarded. To make matters even worse, on completion of the job, I received an invoice for the outstanding amount quoted at R1400 per square meter and an addition bill for a step the team decided to build without informing me that this would incur additional costs. By then I have paid an additional R6500, and informed Ryan that the bill was settled. Six weeks later I received the same bill for the outstanding amount, informing me that I owned the company money. Ryan first responded to my mail querying this, saying that due to personal matters he made a mistake calculating the price. When I responded that I couldn’t be expected to absorb his miscalculations, he threatened me with legal action, warning me to read up about his lawyer. During this job I have been deceived, disregarded, and treated like a *****. I will not recommend doing business with this man or his company to anyone.