Mondo false advertising Vodacom specials

I ordered a Vodacom sim on line from Mondo, special was running from May 2019 till 7 June02019 for 30GB ( 20 during the Day and 10 midnight) I was contacted by a lady with DNB code (031)spoke to a lady who confirmed that it is a 30GB and that I will only pay a prorata balance monthend which will be less than R179. I receive my the sim and had to pay 100 after 48hour of activation( but I was told I would pay monthend) i noticed that i was give 20GB (10 during day and 10 midnight) i went to a Vodacom shop in Carnival and they advised that it is 10 Gb because i received the sim mid month. today is the 1st of July i checked and i am still given 20GB, was this a **** so people can purchase the Vodacom sim of 20GB or False advertising from Mondo site i tried contacting them this morning and reached out to them on Facebook, i wanted a 30GB sim and did not order 20GB sim contract so i don't want this and this is unacceptable.