MTN de*****ing

So I have an account with Mtn for the last 5 years then I left SA to work in Tanzania for 2 years. I was in SA in March, tried to upgrade and I was told my permit expires in December so I cannot renew. My 24 month contract expired in April and after paying all my premiums I'm told I owe them money because I did not cancel?? My wife paid the last premium and told them I was not renewing, they insisted on me notifying them but I was working in the bush with limited connectivity, the email I sent them bounced back. Now I'm back in SA and the issue is with legal, I cannot get hold of them. Left a number for them to call me 3 times they never did. Emailed them and they responded 4 days later telling me I did not notify them so the account went onto a month to month basis! How absurd! A 24 month contract is a 24 month contract unless both parties consent to an extension. I feel MTN is using its muscle to armwrestle a clients into paying extra money when contracts have expired. Have been informed I am not the only one with the complaint. I think this is de*****ing clients, the staff never tells you these terms and conditions when you sign a contract. All I want is to migrate to prepaid or upgrade without paying R3000 of services I never used. MTN looks like a ****** more than anything...really sad!