Grandfathered Simple Choice

I am also grandfathered into the simple choice plan. I've been with T Mobile for 17 years we have five lines. I called to see if we could add a line and they said sure! After the rep tried, I was told we were not able to add the line. Then I get my bill. I was charged for four days of the magenta military plan and I'm not military so when I called, they said that's how they add a line they upgraded it, add the line and then downgraded it, they said this is a normal way they add a line to the grandfathered plan. The whole thing was crazy. Why should I pay for the upgrade? I was never informed they were going to do it. They also removed all our data plans and one of them was unlimited high-speed data for $10 another grandfathered plan, of course we can't get that back!