ERROR: The account has no invoice in Failed Billing

[#1]

My internet was cut off for late payment. I don't use Direct Debit with PlusNet because I have NO confidence in you using the DD system competently and I cannot afford you screwing up and taking more than you are entitled to.
Anyway, I paid and have the text message to prove it but am currently unable to continue doing my work on-line because of a fault.
I get the message: "ERROR: The account has no invoice in Failed Billing".
When I try and speak to someone at your egregious organisation I am told there is a 45 minute waiting time. I wait on hold for 20 minutes and I am then cut off. 
PlusNet is appalling. Your so-called "awards" should be used in litigation against your business under the Trades Descriptions Act.
PLUSNET = TOILET

[#2]

Hi there,
It looks like the invoice was issued on the 5th and paid on the 12th, so you certainly shouldn't have been cut off there? From checking your connection history it would seem there's an intermittent issue showing though am not sure why the lack of connection - but I can't see any notifications regarding the service being disabled:
<img src="http://ccgi.psmith12.plus.com/visradius/generated/image13581634601810.png"/>
If you're still seeing those irregular drops I'd recommend raising a fault to us at http://faults.plus.net