400 mb data for 12 months on buying phone

I have bought a smart ph at hi fi corp.at n1 city cape town in des 2018.the deal was pay as you go.with 400mb data montly for 12 months.then the trouble started.firt I must buy 12 airtime to activate the data.nothing happened.then anotherr12 data I must sms SMART to the no given.nothing happened.every time the r12 gets eaten away with sms,s.it has been 3 month now .lately they do not response to my e-mails