I was overcharged on my water bill by 200%, during a time I was on an especially tight budget.
Oh god..They do that to me TOO! And we have poison water! Are they going to fix it?
Yeah, they admitted it was a problem on their end and reversed the charge.  I had to waste literally hours on the phone with them!
Oh..the phone part is the worst! And being transferred and re-telling the story! I am glad they reversed it though! Most companies won't!