no internet for 24 hours

New T-Mobile internet user here.  I just experienced a more than 24 period of no internet. Prior to that my reception was excellent.   Messages to move router, etc.  Tried that and nothing.  Also tried and was unable to contact support.

So, sometime during the night my service started working again, without any changes on my end.

So, what happened?  Can I expect this to occur again on busy days, or was this just a one time problem?