Stuart Stone
The choice is up to you.
Dear Blah Blah,
Further to the notice of date (date of your notice), 7 days has now passed without receiving ANY invoice from your company.
As stated in 7) from the notice dated (date of your notice), this matter is now considered closed.
Now you have given them every opportunity to produce an invoice & according to 7), both parties are in agreement that no obligation exists. If needs be, you can swear an affidavit to these facts ;)