airtime voucher not valid

Hi I bought two R12 vodacom airtime using OTA edgars mobile on my account. The 1st voucher I bought when trying to recharge it says voucher already used<br> So I bought another 1 which says invalid I must refer to my query to my dealer, which in this case is OTA Edgar's. I want my airtime it is already billed on my account but no airtime. This service is really starting to annoy me, they r not trustworthy in terms of delivering on time. So I'm done with them I don't need unreliable but quick to bill nonsense people in my life