First poor experience

So I have three lines with USM, two added more than two years ago, the third added about a year later. The third was added a few days earlier in the month, because I moved it from a yearly plan on another carrier. I reached out to CS via chat a couple weeks ago, asking if they could add three days to my line 3, so I don't keep getting billed twice per month for my lines, even with consolidated billing on. They told me to come back today, because the renewal time was too far out, so I did. Only for them to tell me they could not extend my third line, but they'd be happy to shorten my other two lines to sync up the billing.

So I was looking for a win/win situation - I get three whole days for free, they get to only bill my card once per month (saving them CC fees each and every month), and their answer was to cut off three days of two of my lines.

I'm not going to turn off consolidated billing like I threatened (in a minor fit of anger, my bad), but I'm not cheating myself out of plan time to make their life easier. Very disappointing.