Cancel Vodacom Contract

I have a data contract expiring in 2 months and I'm trying my best to give notification to cancel.

I've called multiple stores - but they don't even answer . I've tried emailing - but no reply to that I even tried walking to a branch - but they need to call the call centre

I don't have time to sit on the phone for 30 minutes - with tears in my eyes, how do I give notification to cancel ?