Disappointed customer about Vodacom and their work ethics, how they value their customers.

I had a pay as you go number for some time on my tablet. So basically I was and still currently using Whatsapp on it. Now I've been with Vodacom for many years, since cellular phones came out. The other day I realized that my tablet did not have any signal, so I contacted Vodacom and there response to me was that my number has been recycled, and that someone else is using that number. So I was very furious about this, because of security reasons. Can this other person see what's happening on my tablet and also, Vodacom is a professional company. Is there no company policy or ethics to contact idiots like me to tell me that my number has been recycled, and that I can never use that number again because it belongs to someone else. But strangely I'm still using Whatsapp on that number. I'm very disgusted and disappointed with Vodacom with regards to this. Why can't they send you a message or a call saying that they going to recycle your number. And this is not the only issue that I have with Vodacom aswell. This is not good business practice from a big company like this.