CellC ****** blocked number coz of arrears of 7k (1k paid April) now they've doubled the amount to 14k!!!!!

Had an account which was in arrears but ending March 2024. Amount owing was 7k I paid 1k now statement says I'm owing 14k coz "early cancellation " I didn't cancel or ask for any cancellation, Cellc canceled and now they demand that I pay for that cancellation fee of 6k when my contract was ending March 2024!!!! Madness I won't fall for such, the only amount I'm willing to pay is 6k also number was blocked since it was owing so I wasn't using services!!!!!