Line Suspension fees

I have a mobile hotspot and plan. $50 a month. I have had it for years. Recently, I had need to add a higher level of service and obtained a unlimited hot-spot data plan for $160 a month. At the time I suspended my $50 hotspot line.

Over the years I would use the $50 a month hotspot when we RVed. Active for a few months, then suspended, paying a $10 fee until I needed it again.

So, here I am a few months after getting the new $160 unlimited data hotspot being changed the normal $50 a month for what I thought was a billing error on the old hotspot. 

I called T-Mobile today, only to learn they changed their policy in November 2024. So why wasn't I told this when I obtained the unlimited system, as that is when I "suspended" my $50 hotspot line in January.

 Buyer, beware they say.  Never thought I would have to say this about T-Mobile.