Samsung shy's away from S3 mini problem

I've given up hope with Auto page then contacted Samsung to explain my dilemma with the S3 mini, noisy back ground when talking to people. I have explained to them that my phone was sent for repair 5 times and that each time the phone comes back the phone does exactly the same. We even changed sim cards as was suggested by the repair technician. I asked them to please replace the phone as I use the phone to conduct my business, I did not ask for a better phone or upgrade merely for a phone that works. In the last few weeks I've been on the line with Samsung numerous times of which the last call was on the 27th of August 2015 I was left to believe that the person speaking to me was the most capable person and that my problem should be resolved within the day but just like the previous 3 conversations at my cost no call back and no solution. Since then I came to hear that their is more S3 mini with the same problem.