Non-compliance

It took two people to call me to "migrate" my contract. They told me I'll be paying less for more data and whatnot. The first month was exactly what they said would happen, but the second month they took almost double my installment which left me struggling so bad that I had to take out a temporary loan just for food and shopping. Apparently it's migration fees, which they only apologized that I wasn't made aware of. And the worst part is that I spoke with a lady from billing who said they don't do DSAR which is very unsafe for customers. What protection do we have against them and it's basically he said, she said.