Everybody has to do what they are comfortable doing. Me - I would deal with it at every level until they made it right. That is just me. I could not rest until it was corrected.
BTW - interesting story - Lowes - years ago I found the Lowes' bills confusing - if you chose the 24 months no interest (or whatever it was then) instead of the 5% off, it was lumped into your bill in an odd way - very confusing to figure out what you owed regularly and what you did not owe due to the deferral. I called several times - they agreed it was confusing - and at one point I asked - what if I just bring in the bill and you figure it out and tell me what I owe. They said that would work. I then wrote to the Chairman of the Board of Lowes - maybe it was the CEO - I think it was in Atlanta - explaining the confusing nature of the bills. I received a call from the sweetest southern lady - secretary to the Chairman or CEO. She said the chairman had received my letter, would discuss it with staff and see what they could do, but likely they could not help because their billing was handled by a separate company. Anyway, about a year later the same lady called just to see how I was doing, and then I got another call later. Just to check in on me. True story.