offer wrong service

I bought an airtime of R12.00 AND i Got the message that dial *123# to check your offer and did that and selected the offer of 180 min voda to voda for 3 days for 12 rand got the message that you have successfully purchased the 180 min for 3 days for 12 but when I check the balance I found that the offer is just 60 min for that 12 this happen several times.