British Gas chasing a bill 10 days after it was paid.

SydSnott

Around Nov 10th, I received a gas bill for the last Quarter, I scheduled it for payment with my Bank and thought no more about it.
December 1st, I received a chaser and checked my Bank statement to find the bill was paid on November 21st.
Despite them saying "if you have recently paid, don't reply", I informed them the same day that this bill was settled on November 21st and that they should take more care in their accounts.

December 10th, I received another chaser, threatening that I would incur an additional charge of £13 if they had to pass this debt to their collectors!
Again this contained the paragraph saying "if you have recently paid, don't reply", again I did reply, with a copy of the payment record as shown in my Bank statement, along with the somewhat salty salutation borne of frustration "Now F**k off".
December 22nd I received their solicitors letter demanding payment of the bill plus the additional £13 already threatened by BG.
I immediately responded to them with copies of the original bill, the payment screenshot of my Bank account, BG's first chaser, my response, their second chaser and my response, and requested their comments.
December 29th, I received an unsolicited (pardon the pun!) letter from BG enclosing a cheque for the total sum of the bill currently being chased for payment with the statement "to settle your final account"!
Seems we have now gone from panto land to Alice in Wonderland!

Meanwhile, since the banks are now open, I called mine and they agree the bill was indeed paid on November 21st and will send me a letter to that effect in the next few days and I will forward a scanned copy to the solicitors upon receipt!

Any advice regarding the surprise cheque?
I'm minded to cash it just to cause the same "Mischief and wanton harassment" that they have INTENTIONALLY caused me!

Farway

I'd cash the cheque, but do remember it is not really "your money" and expect BG to ask for it back later, once the cogs have ground on a bit. 

"Mischief and wanton harassment" that they have INTENTIONALLY caused me! "  Doubt it is intentional, unless they really hate you. Just normal slipshod service

Given the wording of the letter, "to settle your final account", I'd check on line to see you are still a customer, nothing would surprise me if your account had inadvertently been closed and BG deny all knowledgege of you

WiserMiser

Send BG a written communication headed COMPLAINT and go to the Ombudsman upon receipt of a deadlock letter or after eight weeks if they don't send one.

I'd be tempted to take them at their word and pay in the cheque.

Similarly, unless you're about to apply for a mortgage or other loan where your credit rating needs to be really good, I wouldn't bother to prove my innocence, I'd tell them to do their worst and take me to court.  Maybe send a letter to their CEO (details at the CEOemail dot com website).

If they've put anything adverse on your credit rating, add an explanatory note and make a money claim against BG for all the aggro and damage to your reputation.

Robin9

Don't waste your time with phone calls, emails and sending them copies. I think cashing the cheque will cause you more problems.

As @Wisermiser  just send them a COMPLAINT   

SydSnott

Thanks everyone for your thoughts and advice.
lol, The comment by @Farway made me smile because having read that sentence, I had to go and look to see if the boiler was actually working!   
I'm not Cristian enough to believe as he does that this was other than malicious, but I'm trying to resist the temptation to cash the cheque!
@Robin9 and @WiserMiser, I think this is likely the best and safest route to follow, though I do feel that some measure of punitive recompense is appropriate.

I've had it way over the top of my head since November with life's idiots:
Nov 15th, I had an ISA Maturing, likely to exceed the then FSCS cover amount for re-investment, so Issued two Partial transfer requests, first one enough to stay within the "cover" when matured and the remaining bit, to another provider with a lesser ISA return.
Dec 1st, I receive an email from the expectant recipient of the larger amount saying their pull request was returned due to "Lack of Funds" 
Turns out that the lower value recipient bank despite having confirmed that this was a "Partial" sent a pull request for not the full amount, but for eight hundred thousand odd pounds!!! 
The Clowns at the holding bank just shrugged their shoulders and gave them the full proceeds also despite knowing it was a split transfer and was way less that the requested amount!
It has taken fully two months for the funds to eventually re-appear (still under ISA status) for reinvestment as a whole since the FSCS cover has extended sufficiently to make this a safe option.
Honestly, I wonder about the qualifications/qualities required to enter the Banking profession these days!
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