Cell C
Cannot access "My Tools" or "My Account"

I have spoken to consultants on three occasions with regard to my online problems. Each time I have had a prompt response which should have sorted the problem but hasn't! When I access "my tools", an old phone number comes up automatically, this number ceased use by me two years ago. When I replace it with my new number I get the response that it is not a valid number. Similarly when I try "My Account ", my phone number is rejected. I have tried on my mobile as well, with the temp P/W that CellC sent, but that doesn't work either. CellC has twice SMS'd a P/W for my current number, but it is rejected as before. Can someone please add 2 & 2 together?!!