No Pin received from unipin

I bought vouchers of electricity from a garage last week. On Saturday my electricity metre ran out. I followed the instructions on the voucher but received no pin 2 hrs later. So i bought a little online. It's now been 2 days later and I still don't have the pin from the vouchers I bought. I keep buying a little at a time online hoping that the sms'swill come through because it was quite a bit that I bought on the voucher. This is ridiculous.