I have paid my account, but every time I phone, they try to help me then the problem is fix but once I put the phone down than nothing is working not 4G nor 5G this issue is happening over and over

I have paid my account, but every time I phone, they try to help me then the problem is fix but once I put the phone down than nothing is working not 4G nor 5G this issue is happening over and over . I tried to watch Netflix but now it tells me that I have network issue. I feel like canceling my subscription