Dr. Tech Global LLC refund ripoff SAN FRANCISCO , California

I purchased an item from this company through eBay. The item was defective. I returned the item to the company and was sent a replacement which was also defective. I returned the second defective item and requested a refund of the original purchase price, and for consideration of a refund for the return postage charge on the second item. The company replied that return postage was the buyers responsibility, as stated in their policy. I asked for consideration of the fact that I had returned two defective products at my expense and if the company would consider reimbursement for the shipping charge of only the second item. The company has since failed to reply to email messages. They did post a partial refund of the original purchase price to my bill paying service, but have since failed to respond to numerous inquiries asking why only a partial (80% of original price) refund was given.