Unknown 404 numbers showing up on my usage log

This is happening to me as well. I noticed this about a year ago. One year later I'm sure there are  thousands of texts and phone calls that are listed on my usage yet I have never called nor text these numbers. They even have outgoing messages and calls listed in my usage that I've never ever ever replied to via text or called these numbers. T-Mobile  can't tell me what they are or where they're coming from. T-mobile only tells me that my account is perfectly safe and nothing is out of the ordinary. It drives me crazy. T-mobile who claims to be so efficient at security yet they can't fix this and they can't tell me what's wrong so I've just given up on calling them about it. 
I have done my research. It seems to be a very serious issue. Criminals steal or use other networks and phone numbers to mask their own malicious activity. Why would anyone do this unless they're using our numbers to hide their actions. I'm afraid that I will get blamed for whatever they're doing as my research says it appears as if the victims can be blamed. I'm very concerned but it's falling on T-mobile's deaf ears.