Poor service and lack of knowledge

I'm a new customer. I completed all info for Mtn LTE and selected delivery to be done in 3 hours. Almost 24 hours later, they advised that payment is outstanding, yet they were supposed to debit (after I had to verify my bank details through their process).

Now a consultant says that they take 3-7 days to deliver. Why make promises online to deliver in 3 hours?

Kindly advise whether I should cancel?