How can I ask So Energy to resolve our £524 bill issue?

We have a long standing issue with a missing payment to our energy supplier ESB Energy, now part of So Energy.

The change in ownership was poorly communicated and resulted in an outage of online payment systems, as well as statements.

This required us to pay our utility bill. January of £524.82 by cheque. The money left our bank a month later but was never credited to our energy account.

Many attempts to resolve this issue have been unsuccessful, as did an official complaint in May.

So Energy acknowledged the issue and apologized for the delay, but did nothing to resolve it.

Last month I received an email from the company with the subject line: "You are not paying enough". It said, "We've noticed you've fallen behind...we need monthly payments to prevent your account from falling too far behind."

GT, Ilkley

on the merger.

Without account access, you were unable to make an online payment and after back and forth, you were advised to send a check to ESB office in Manchester.

Unfortunately it happened just as your account was migrating to So Energy . It doesn't help that you were advised to mail the check to an office that no longer exists and, when it arrived in the correct place, was not posted to your account. This has now been rectified and your account, which is now linked to the smart meter, is up to date, bringing this saga to an end.

So Energy says: "We strive to provide the best possible service but, on this occasion, it appears that we have not succeeded, so we apologize for that. Email us at consumer.champions@theguardian.com or write to Consumer Champions, Money , the Guardian, 90 York Way, London N1 9GU Please include a daytime telephone number Submission and publication of all letters are subject to our terms and conditions