Your expectations are very different to mine.
I'd love a company to message me and inform me (without me asking or querying anything) that they had me on a lower tier by mistake and I would be refunded for the entire duration.
Going by that thread you posted he's already been assured he'll receive every penny back.
I'm sure he would have got the same result by phoning back and getting someone senior enough on the phone.
I've been fighting with Scottish Power for nearly 2.5 years to fix the billing on my Gas Account.
6 official complaints registered with the company (they keep closing them), 2 upheld OFGEM complaints, 3 separate compensation claims paid out and my bill is still screwed beyond belief.
I've been with Plusnet since October and not had a single issue.
Couldn't recommend them enough.
I already have 2 referrals active, correctly discounted on my account.