Bad Service

Bought a new phone, ever since im struggling with services like *111# or *100# or there is no network an most of the time my incoming calls goes to voicemail atleast. Everytime i need assistance on 111 im am told to reset my phone and take out the battery and sim card. That will resolve the problem temporary until i was told to buy another sim card but the problem persist. This happened within the 7 days but i was told theres a network problem and i should be patient. Now 7 days has passed long ago and i cant return the phone. If i put my simcard on another phone, it works very much fine. Now i cant return it and im stuck with a skorokoro. No wonder people keep switching to other networks.