stumped

I've been a long time very loyal tmobil customer! Diagnosed with a very aggressive cancer but losing my battle. Because I live alone it is so important to me that I have a working phone in order to contact emergency services, my drs and my children and grandchildren! I cannot begin to tell you how many times/hours I've spent on the phone with T-Mobile "supervisors" in an effort to get them to understand that my phone (iPhone 12 mini) is  all but impossible to use from my own house unless I walk outside and find the perfect spot to make a call! Because my treatments (chemo and radiation both) I'm no longer able to work so money for me is very much an issue with zero income. Countless times I've explained this situation to tmobil supervisors and multiple times I've been assured that they were there to help me "a valued customer" however still my phone has connection issues from home and still my phone bill is "Astronomical" ($400+) this month even though I let them talk me into re connecting my Tmobil  home internet and still my phone has connectivity issues and this month I've noticed that Tmobil is charging me over .$200 for not returning their home internet device that they have just now hooked back up and are charging me $80/month! I just cannot understand how Tmobil can justify these charges and the "broken promises" their supervisors have made me in the past after I explained my current situation! Mind you I'm a 59 year old  but I only desire to have decent service so I can talk with my grandchildren in an effort to create memories for them to remember "Papa" by when my battle finally ends! I'm not asking for anything free nor do I desire anyone feel sorry for me I only want a service I can afford that "actually works from my own house" that does not cost $400+/month! Thank you kindly for allowing me to express my concerns, May GOD Bless each of you and your families always!!! ✌🏻🫶🏻😊🙏🏻