Late Invoicing result in Bad Credit record

Vodacom does not send invoices in time, invoices is only send after 7 days after payments have to be done, resulting in there speeding ITC bad payment record. Thanks Vodacom!! I never skipped a payment, I only payed them short one time, as I did not have the time, going through all my contracts and calculate all my contract payments to be paid. I just pay that I normally pay. Now I am blacklisted for a R222.00 short Payment. I have phoned the customer support centre, and after I have been send from one department to another department, after an half an hour they have promised me that they will send me a letter that I have payed them and get the record of my name.After 2 days NOTHING!! an hour of frustration wasted!! Phoned again, NO they cant send me a LETTER thanks for telling me before!! They will send me a statement! So the statement will not clear my name and is useless for my financial services. So this is how Vodacom treat a customer with 3 personal contracts and a Business contract. worth more that 10 times they blacklisted me. And thanks for your loyal support. No Letter for payment! <br> Quostion? Who's fault is this now??