Sim No removed from Network without notification to customer, even though I received calls on this phone up until the 09/01/2018

I purchased a pre-paid sim in order for me to utilise this for Whatsapp purposes and other Social Media`s Platforms for my Business. Whilst I was sorting out my Wi-Fi, I topped up with airtime to to allow me to load data to the phone. As soon as my Wi-Fi was connected I no longer had the need to load data to the phone. I used this phone without loading airtime I think for more than a year. Whilst I never made voice calls on the phone because I had no need to, I made Whatsapp calls and I received VOICE calls up to the 09/01/2018 with this number. I recently needed to use the phone to make a voice call so I decided to purchase airtime to allow me to do this. When I wanted to load the airtime a message popped up on the screen advising that this number is not on the Network. On calling Cell C they advised that the number was removed off the data base, this WITHOUT ANY NOTIFICATION TO THE CLIENT THAT THEY WILL BE DOING THIS. I was advised by the Call Centre agent in order for me to have the number activated I need to purchase a new SIM and do a Sim swap, which I did. On calling Cell C again to have the number activated I was advised that they Cannot do a Sim swap because the number has been inactive for more than three months. This bearing in mind that I still received calls on this number in JANUARY 2018, and suddenly in February it is off the system, which is not even a three month period. I AM EXTREMELY ANNOYED BECAUSE CELL C DID NOT EVEN HAVE THE COURTESY TO INFORM ME THAT THEY WILL BE DOING THIS AND WHETHER I STILL REQUIRE THE NUMBER, OR EVEN A POSSIBLE SMS ADVISING THAT SHOULD I NOT TOP UP, THE NUMBER WILL BE DISCONTINUED. I ALSO CANNOT FATHOM HOW THIS NUMBER IS DISCONTINUED IF I AM STILL ABLE TO USE THE NUMBER ON WHATSAPP. I NEED THIS NUMBER TO ENABLE ME TO CONTINUE WITH MY BUSINESS AND CELL C IS NOT EVEN WILLING TO ASSIST ALBEIT THE FACT THAT THE NUMBER IS IN THE SYSTEM TO BE RECYCLED. What they need to realise is that things are evolving in the way business is done and that they cannot dictate how one utilises their SIM CARD.