Overcharging stupidity

[#1]

We are a new Plusnet business customer so we looked at the first bill a bit more carefully than we might look at subsequent bills and noted we'd been overcharged by 18p, which Plusnet fully accept. Plusnet said they'd repay the 18p into our bank, but we said don't do that because we'll incur a bank charge of 22p and suggested they simply credit the 18p to our account. They said they couldn't do that, so we said OK, then in addition to the 18p, please pay the further sum of 44p into our bank account which will cover the 22p bank charge we will incur plus the further 22p bank charge we will incur as a result of them refunding us the 22p (make sense? - makes total sense to us). Currently Plusnet say they don't understand why we should be incurring this charge and are also saying that it's not their responsibility. But we're a business and as everybody except Plusnet seem to know, banks charge business customers (this makes me think that Plusnet aren't really set up to do business with business customers). And as for 'responsibilty', obviously the whole storm in the proverbial teacup has a risen because of Plusnet's error in overcharging us, so they're clearly responsible. Suffice to say our confidence in Plusnet is wearing a bit thin - and it's only month 1 

[#2]

If you get charged 22p to transact the refund then surely the total payment should only be 18 + 22 = 40 and not 18 + 2 * 22 as you only need to be paid once of 40p!
As an addendum, I would see your logic applying only when Plusnet had already paid the 18p to your account, as you would now be -4p, but I don't take that has happened from your post.

[#3]

The majority of Plusnet biz support agents will have no concept of how business banking operates. You'll need to escalate to team leader or beyond if you continue to hit a brick wall.
Like mook, I'm struggling to understand your math though.

[#4]

Perhaps the OP was told that the subsequent 22p would have to be a separate refund thus incurring the extra 22p charge?