Invoice

Its has been 2 weeks now since i had spoken to Patrick with regards to the contract i took, after we have agreed that i am cancelling the contract so he must send me an invoice to pay for the tablet that was delivered, he agreed, even asking me as to when will i pay it, i told me the 25th since it was my pay day, please note that i do not want a debit on my account, Patrick told me i need to pay R1915 for the tablet, i am still waiting for the invoice he agreed to sending me two weeks later.