Help! Phone not ringing, calls directly to voice mail

I researched the "related topics" and thought, great I'm not alone then noticed that the complaints were from 4 years ago!!! I switched from Sprint to Tmobile the end of May. Was told I would have coverage in Alaska. NOPE.  Hell, the service in Phoenix and Seattle was sketchy. I cringe every time I see a Tmobile commercial touting their incredible coverage.  Okay, back home in Florida.  I get notifications of a voice mail received and the phone doesn't even ring, while I'm holding it.  I waited week for return calls from the IRS, food stamps and daily calls from my oncologist's office.  Guess where they all went. Do you know how difficult it is to get a return call from the IRS agent you are working with or the food stamps office which has awarded me $20 per month due to failure to make an appointment which were 2 of the calls which went straight to voice mail.  Seriously, these are not people who answer when you call them back, you go right back into a call queue and wait another 2 to 3 weeks.  Totally unacceptable.  So, I call 611 and vent.  We don't have service in Alaska, why weren't you on international roaming, geez, I don't know, maybe because it wasn't offered by the liar in the store (who also told me I wouldn't get another bill from Sprint, but did automatically deduct from my account along with the new Tmobile charge.  Then explained the last 3 weeks of no ring, just message to the person I could barely understand.  I was transferred to my "team" in Tampa, fantastic now we are getting somewhere.  My "tower" is being updated. So what, not my problem, wait yes it is.  Let's change some settings, none changed, they were all correct.  Let me overnight a new sims card to you and I will call you tomorrow at 5 to walk you through so you won't lose so many contacts as you did with the "in store guy (liar). No call, this was last Thursday and I have been too sick to deal with this.  However, late last night, no ring from my dear friend whose son had just passed.  And, today, oncologist straight to voice mail.  Called back, apologized and awaiting another call back.  Biggest problem is the fact that I don't know they are even calling until a voice mail notification at the top of my screen. Doesn't even show up in my call log. Never had these problems with Sprint, not until I was rolled over into the company with the "greatest coverage".

Any suggestions before I switch to a service that actually works.

Thanks, Kathy