Monitoring my phone!?

so my dads phone contract just ended and he decided to get a new contract on the same service as mine, metro pcs. and now i got a tex saying my account has changed and trhe amount due is 76.00 instead of the normal 40.00. so now i know he linked the accounts.... so does this mean he can monitor my phone?! or recieve my texts that i send or recieve? ... is there any way he could be monitoring what im texting? thats what id like to know... i know some services have location things on them, does metro pcs have that? someone please help please