Rebath of North Texas No warranty Carrollton, Texas

Rebath of North Texas installed two showers for us two years ago and gave us a lifetime warranty.  We used them because they were a franchise.  They are not to be found.   I called the man who owned the company and he says there is nothing he can do. He sold it to someone else and he thinks that it was sold again to another man.  They are suppose to take care of the problems.  When I called they asked if I had the original invoice and proof of payment.   I finally found them and now they wont return my calls.