Error Message Connection Problem or Invalid MMI Code

I have Metro Service, so I use the T-Mobile and the Universal code several times and I keep getting the above message. I have suspected my phone is hacked as my ex husband knows way too much of my personal life plus strange downloads, battery drains quick and the Stage Fright Test App thru Google Play Store tells me it is. Any thoughts and/or advice and what can I do. Factory reset my phone multiple times and even taken it to several Metro stores and they think I am crazy as they say it can only be hacked if he has physically had my phone in hand. Bought 6 phones in the last nine months and each time its the same. Within hours of havibg it I have all these strange downloads and updates and stuff I did not put into phone.