Faulty products ,bad after sales service

We had an armed ******* and were told to replace our items that were stole at New World. Outsurance would give us a credit at New World. When we were replacing all the items they were exceptionally helpful. 3 Months down the line the amplifier had a problem and it took 1 month in repairs through New World . 3 Months later the amplifier gave the same problem and went in for repairs on the 12th June and we got back a replacement model the 11th July. They now are only giving us a 3 month guarantee on the new unit. This is just not acceptable.