Express Transmission Bad Rebuilt Transmission Fort Lauderdale Florida

Express Transmission rebuilt my transmission in my 2006 Chevy Express 3500 on Dec 11 2012 they gave me a 12 month or 12000 warranty whichever comes first.  After 3 months of it having it rebuilt I notice my rear transmission seal was leaking transmission fluid, I brought it back to them they fix it.  After May  and 7695 miles later it was not shifting into 3 rd gear and hesitating in other gears  I brought it back to them  and the mechanic  notice there was metal shaving in the pan.  They told me they would have to rebuild it again at no charge and I would have it back in two days.  I ask mechanic who worked on it was it fixed right and would I have anymore problems and he gave me his word that it was fixed and I would have no more problems. 

I asked the mechanic does the warranty start from the second time it was rebuilt or does it start from December when I first had it done, he said in December.  It is now September 4 months later and 6371 after second rebuilt of the transmission it’s having the same problems again.  Now that my warranty is over with,   I was 3 months short of the 12 months and 2000 miles over the 12000 miles of the first rebuilt.  What gets me is they were referred to me from a friend, also my brother recommend them and the mechanic gave me his word that was fixed and now I am going to have it rebuilt again from another transmission shop.