False advertising

I got an mtn sim card then i received an sms that if i download mtn momo i will get 1G free,ok there i used my data go download mtn momo thinking i will get data but little did i know,that was false advertising,i waited two days without getting it,then i called mtn and an agent tells me no the promo is finished now,but why if its finished you still advertising it ???as a customer i saw what i saw and thats what i must get,mtn is full of lies,they are getting people to download that momo app by promising data that is not there.