Vodacom - What are you playing at!?

On Monday 6 Mei 2019 I called my local Vodashop in order to enquire about the Vodacom "****le" as I needed internet conectivity. The gentleman I spoke to informed me about a 30 + 30 meg contract deal at R299 per month, which was still valid but would expire on the next day, the 7th. I rushed down to the store concerned and filled in the contract forms and furthermore, purchased the ****le and sim card for just over R700. I provided all my financial documents as required and was told that activation would take between 24 - 48 hours. On Wednesday, the 9th, the deal had not been activated. No reason was given!? I continued contacting the store every day subsequent and was eventually told that they had a number of the 30 + 30 gig contracts outstanding. On Wednesday the 15th I was told that I did not qualify for the contract!? I then threatened to return the ****le and simcard for a full refund! Yesterday the same gent contacted me and offered me a 20gig deal for R199!? I desparation, I agreed. The contract was activated on the same day!!! My question now is : Why would Vodacom do this? It obviously had nothing to do with my financial suitability. Why was I offered a deal which was later withdrawn? False advertising? The 20 gig deal entails me having to "top up" at huge expence after my bandwidth runs out. I am very dissappointed in this company whom I have been doing business with since their inception!! Could someone please explain.