how to leave a good customer service review?

I recently had some issues with T-Mobile and I had to call their customer service line three times to try and resolve the problem. Unfortunately, I was put on hold for an hour each time and the issue was not resolved. It appeared that the agents were ill-prepared to fix the problems. Prior to this, I had called them about some network malfunction, devices not working properly, and my child not being able to make or receive calls. I even replaced the phone, but the issue persisted. Due to these recurring problems, I am considering leaving T-Mobile