Secure Encrypted Login

I see my problem is not a new one; customers complained about the issue of a loss, in my case, of 2GB of data, for the reason given below. My data loss was on about the 29th of May 2020. I had purchased 2GB of data on the 28th only to find I had had lost 2GB which was shown as Secure Encrypted login. I have no idea what this is and no-one at Vodacom in iLanga mall know what it is. I am a self-employed pensioner and simply cannot afford to lose data like this. It may well seem to be small loss, but I only get 30GB a month.