what to do if a china phone my dad ordered from online signal from service provider is not working?

My dad ordered a phone for me called 'T9700 MTK5989 Android' 1 month ago. its a china phone which costed $200 The signal first goes on then after like 2 minutes or 3 the signal goes off. And also I checked with a signal program on google play. It says that the SIM card cannot get the external ip address number. It also shows the status as disconnected. I ordered this phone from www.kaylaelec.com it arrived on time and everything but it is a very bad phone.. I tried on other SIM cards also. I tried the t-mobile and then I tried gosmart which I tried on now. They work on the phone but the phone's signal is not remaining there. I don't think my dad can return it.