phone won't ring calls go straight to voice mail

i have been having the same problem in the last month or so that calls made to my phone would go straight to voice mail and they do not show up in the call log. i would not have known if it was not my family who called and told me about it. It is happening randomly. Most times my phone is simply placed on a table. As an example. Tonight my daughter (TMobile also) called me.  Nothing rang and she didn't leave a voice mail. i only knew she called because i received whatsapp msg from my sister because my daughter called my sister looking for me.  I was actually in the same house as my daughter. When i went to her room, she called me to test and it came through. i have already called T-Mobile tech support and had a ticket opened. He did a few things with me on the phone. He was going to send someone to check on the tower nearby and a week later i have heard nothing and the problem is still there.