Discovery dental las vegas Dr. E Mersha Discovery Dental Partial denture that keeps breaking. las vegas Nevada

Partial denture that keeps breaking. The first time it broke it was a few months after I paid them some $3000 for a partial denture. They fix it and now the second pin broke. When I called them, they told me it's almost a year so it'll will cost you $75 to fix it. When I came to the office they presented mewith a $200 bill. I ignore the bill and told them that they should stand behind the work that they do. They agreed to ignore the charge, but the fix of the second pin was substandard and within a few hours after the fix the denture is loose and uncomfortable. So now I don't know if I should go back to them or just forget about these clowns and find me another dentist.