I'm trying to work out how you could end up paying £22 to contact (or fail to contact) E.ON. All of their main contact numbers are 0345 ones
https://www.eonenergy.com/for-your-home/help-and-support/phone-numbers
and Ofcom rules state that all phone operators (both landline and mobile) must charge '03' calls at the same rates that they charge for '01' and '02' numbers.
That means that the vast majority of callers don't pay anything at all for their calls to E.ON because they've either got 'bundles' (with loads of 'included minutes' for 01 and 02 calls) on their mobile phones or landline plans that give free calls at certain times (such as at weekends or during the evening, or even at any time).
Even paying BT's standard rates you'd need to be on the phone for 2 hours 25 minutes to run up a £22 bill.