Contract Deactivated Even With Arrangements in Place

I recently fell in tough times and had to prioritize some of my debt , I called Cell C and made arrangements for my late payments , This started in January 2016 , My arrangements was to pay some of the due payments in March and the rest at end of April 2016 , I have done this , but when I phoned to reactivate my line I was told that my cellphone line that I had for 10 years was permanently deactivated due to none payment , But tell me how was this possible ? I made arrangements and the operator that I was in contact with told me there would be no problem as long as I keep to the arrangements!I tried to contact Cell C but without avail since my number is no longer in service they can’t contact me back , when you phone the legal department you have to hold for hours due to none service from them.