Check your invoice!

[#1]

I recently changed my package and included the UK, Mobile, International 500 package.
After a couple of months I noticed I was still being charged for mobile calls and raised the issue with customer services. They refunded the last month's overcharging but then had to be prompted to check the previous months (I'd have expected them to do that automatically if an error was detected.
I suggested that "It's a bit worrying in that customers need to point out these billing mistakes... " and got the following response:
"Unfortunately it is the customers responsibility to check that the bill is correct."
Wow! Surely it's PlusNet's responsibility for ensuring the that the invoice is correct!
I've been a business customer with PlusNet for over 10 years and until recently was pleased with the service, but no longer.
I wonder how many other people have been overcharged in this way?

[#2]

Hi there,
I can see we've rectified the situation regarding the additional charges and I agree with you it should not be your responsibility to check that your bill is correct, by all means if there's an issue flag this to us as you did. It's something that a customer may need to check to see the bill is what they would expect.
I'll feed this back as it could have certainly been worded better towards you.

[#3]

Hi - I checked your invoice for the support team earlier today; I agree entirely with Chris's comments that the wording of the ticket could have & should have been better. However, you were charged correctly! I think that some confusion has arisen due to your tariff sharing 500 included minutes across mobiles & international calls, those 500 minutes were exceeded; you've also been charged for where calls exceeded the 60 minute limit.