Samsung faulty

I bought a phone(ontract) last year , it has speaker problem. When on call people complaint that they can't hear me, I took it to the Grove outlet the technician can't find anything. Secondly to Kolonade outlet and they referred me to Menlyn. At Menlyn they checked it didn't find any mistake, the technician told me that it seems this Samsung came out faulty from the manufacturer because most people are experiencing the same problem as mine