Samsung phone problem

At the beginning of February I bought a brand new Samsung phone from Incredible Connection. On inserting the Sim card, the phone was unable to detect the availability of data on the account and a few of the other functions were also not working, Returned to the shop and was told this was not the first time they had faced such an issue and the phone will have to be sent back for repairs. Three weeks later I still have not received the phone back and the technician tells me that the phone came back but still had the same problem so has to be sent back for repairs again. I feel that this is very poor service. The phone should be replaced in my view.