MGL gas bill paid online but still not updated

[DylanScotland]

I never experienced issues with payment with MGL, although I often either use payzapp or cred.
Usually it does take 3–5 days for the bill to update, but the day you make the payment is counted as the payment date.
First thing to check would be, to ensure CA number paid for is correct.
Else, assuming you have a valid BBPS Reference Number, there should be reason to panic.

If in future it disconnects, you might as well just directly go to their office and speak to them about it. The worse would be a day of no gas.