Bren Tuning Failed to provide items that were purchased. Upton Massachusetts

I purchased software for my car from Bren Tuning; once the sale was complete, the sales rep informs me that the software most likely wouldn't work. After questioning the sales rep he replies with: "Enough with the attitude. It's constant with you. Maybe that's just how you are but you get more bees with honey than vinegar - something to think about.

If you want to have a normal non confrontational email exchange we can work with you, if not I'll just refund it and we can go our separate ways because I'm sick of it."

The sales rep is refusing to answer my calls or return my emails, and I have not received a refund of any kind. I purchased something in good faith believing that they would provide the product and they sold me something that shut my car off, and then made it undeliverable. I seek to get a full refund of all the products I bought from them due to the fact that they are refusing to provide support for their products. 

I can provide the email chain of our correspondence.