Significant increase to Internet bill in 2024

In February of 2024 my Internet only bill went from 76.00 a month to 95.00 a month.  This is a significant increase with no explanation.   I believe I'm on the lowest speed plan now.  It's impossible to get anyone to chat with on the AI chat.  How can I speak/chat with a real person about this?  If I can't get this resolved I will need to switch to TMobile or one of the other providers in my area.