phone has been disabled due to deletion of Google account

I have a LG K7 smartphone. When the phone was purchased I did not know what to do with it, so the sales person at the Metro PCS store set up this phone with a G mail account that was not mine and needless to say the same salesperson is no longer at the store (At the time I didn't have a G mail account) In my photos I started getting nude photos of male genitalia at full attention and female body parts from head to toe. These photos were very very lewd and I don't know who these people are. So there was a place that said do you want to delete this g mail account click here... so we did. I am 68 years old and my wife is 62 and was not aware that deleting the google account would render the phone useless. How can this be repaired and what is the cost< where do we send it. I use my phone for work as I am a driver for a company that I must be able to use maps etc. Please assist me with this because I have tried everything with METRO PCS AND CAN GET NOTHING OR NO RESULTS. Which leaves me no alternative but to try to get it repaired.

Thank you in advance for assisting me in this matter.