iStore Purchase NOT transferred to budget

On the 30th Nov I bought a new computer from the iStore using the Budget Payment option. The total amount of R29999 was meant to be transferred to my budget for payments of R1060.65 per month for 31 months at an interest rate of 7%. It was meant to take 3 to 5 days to do this. To date,15 days later it is still sitting in my credit account. I have written to FNB card and didn't even get a response. This is unacceptable service and needs to be rectified urgently and I need to be communicated with as to what is happening. Please advise before I am liable to pay this amount in full as that severely messes with my cash flow.