delete messages in voicemail

I was receiving NO voice mail.. So I started getting msg in sms and most of the msg was transcribed but it would say 'to listen to all of the msg press 1'. When i  did there were so many prompts and it asked you to enter your phone no.  It turns out it was some sort of like group voicemail if that makes sense.? I've been going through some serious being hacked stuff for a while.  It's my ex and his lowlife scandalous roommates who have all my info. It said I had no msgs even tho I just got the text saying I did.  So I hung up and long pressed one and my REAL voicemail went on.  I went back to the sms and pressed the1 and back to the group thing.  So I did it again and entered my exes #. it said that number was not valid. So I then entered the girl who has hacked my accounts to no, and I entered her phone number, and sure as heck. She also was attached to this group messaging, which meant that if I had her pin number, I could listen to her voicemail which I wouldn't, but she probably has mine and has done so much crap to me in my accounts I can't even begin to start explaining how much anyway the phone number that was attached to the SMS number I called and shortly after I discovered this all of a sudden just hangs up on me I cannot get through to put my phone number in on the bogus, voicemail but this is the number it's somewhere in Texas  1-469-982-5001.  It says "welcome to the sms link service.'  When I did a reverse lookup it now says it's a T-mobile #  but a month or so ago when this first was happening, it did not say it was a TMobile # but I can't remember what it was.