Chase F'd me out of 0% financing after having a separate purchase refunded

I set up 18mo @ 0%, no fee financing through My Chase Plan on a large purchase on one of my Freedom cards.

I made another large purchase later on, long story short, it was kind of a placeholder order that I went on to cancel and have refunded.

The refund for that completely unrelated purchase was applied to My Chase Plan financing, paying off that balance in full.

I learned the hard way previously that extra payments past the statement balance would get applied to a My Chase Plan, but now I'm learning that even a refund will get applied to them as well.

Their solution for me was to start a new chase plan with a 1% monthly fee on the balance (12% annual).

Hopefully this helps someone else. I'm pretty pissed that this is how it's going down as I now have to come up with the cash to cover that original purchase to avoid interest. I'm half way between wanting to just default and churning the ever loving shit out of their cards going forward.