USSD/APP NOT WORKING

i called help line 4 times already looking for help to use USSD/ APP to purchase data and voice bundles but until now it still not working it keeps on saying "there was an error processing your transaction" and until now am still stuck, i mean i have a contract sim there but the service i am getting i do not like it. all consultant keep on saying they will investigate and give me solution in 24hours, but its almost two months now no reply, nothing at all. some of the ref:*** & ***. can someone please assist me ***