O2 (CPW) erroneous information on bills?

p5x

I'm on a O2 contract from CPW which gives me 400 mins+rollover every month. My last month's bill said that I had used 360 mins, with an unused allowance of 160 mins (due to previous month rollover). The total allowance available for this month is stated as 560 (ie-400+160 rollover).

I recently checked my remaining allowance and it said i'd used 405 out of 405 available minutes and had a £30 bill for additional calls. I can understand using too many minutes and therefore getting billed for them but I don't see where they've picked the 405 mins figure from.

I've spoken to O2 billing and they say that the 560 mins must have been a typo on the previous bill and that I did in fact have only 405 minutes this month.

Has this happened to anyone else? It seems ridiculous that they can call it a typo and get away with it, that's completely ignoring the fact how a typo could have occured on the bill since it's not exactly going to be handwritten or manually processed :huh: