Breach Of Client Security

Called Vodacom Customer Service at 23h03pm on the 23rd of November and spoke to one of their *********** agents by the name of Kamogelo (Surname not given) to inquire about my Vodacom number that I've been using since 2019 till unfortunately now...The SIM card was inactive from early this year due to a faulty phone bt every now and again I would use it for other things cos it is registered on my multiple accounts. To my surprise when I tried using the SIM a week ago, the SIM was deregistered and I couldn't use it to access my accounts. The said agent notified me that my SIM was deleted after few months of inactivity and given to someone...The thing that disgusts me the most is the fact that the SIM card is currently being used by someone and what if I tried to do a cash send from an app to that number and sum1 received it? Do they even care about our security? What I failed to understand from the agent about the 'so-called' inactivity rule is that why there was no written explanation on their pamphlet under T's and C's? The explanation given to me by their agent was absurd and inconsistent with their 'only known to them' rule... I've used a different SIM card from 2014 till 2016, the SIM card was deleted and never been allocated to anyone till today. Why did they apply the rule differently? Worst thing is that the 1st SIM card has been inactive for 6 years and never recycled. So why is the SIM card that has been inactive for 4 months been recycled?