Refusal to Extend Time on Payment of Invoice

Re: Invoice [#]
We regret to inform you that we are unable to extend any

more time for payment of the above invoice.
We feel that we have been extremely patient, but if we do

not receive payment in full on or before [date], we shall

have no other choice but to turn this matter over to our

attorney with instructions to use all available legal remedies

to collect the amount owing.
Very truly yours,