Terrible experience with account

I checked my online statement at the end of July to make a payment and total due was nul. I then phoned the call cente on the 7th of August at 9:45 to confirm. I asked the lady 3 times if I need to make a payment and she said no. Only by 1 Sep is my next installment due. All of a sudden im now getting phone calls and emails regarding an overdue account???saying that end of July's payment is overdue and they suspending my account. I am very unhappy regarding this,i will now make a plan to settle my account and not ever again support the TFG group and will inform my friends amd family to do the same.