Why and how did i get a phone nuber in my phone

[Mel62]

I hope someone is up for a challenge.
Well I'm new here i dont know a lot bout all this.with that being said. WHAT a problem i have. My LGStylo 2 phone will jump from. Under network type.
1. EvDo-rev.A
2. IxRTT
3. unknown
4. eHRPD
5. LTE
6. 3G
I HAVE RESEARCHED THIS CALLED MY CARRIER.THEY CAN NOT ANSWER MR QUESTION. They say they NEVER heard of this before.
In my phone status. There is a phone number in my status that is NOT mine.
How did it get there
Were did it come from.
It is a real number i add to my contacts an text this person. They answered.
Plus on my payment history there are 2 payments
1. Reboost card. I get confirmation
2.i get another confirmation
With drawn from account.not mine. PLEASE HELP i dont know this person. He or she can easily find me.
Thank you so very very much.

 

[cpaight]

You could try a factory reset....just be aware that it will delete all the info on your phone and it will be like you're starting with a brand new phone (re-linking accounts, re-downloading apps, any photos will be gone, etc).