Draft Summons a year after cancellation

I cancelled my contract over a year ago after having it for the full 24 months. The final debit order went off without issue, and the final invoice showed a NEGATIVE balance due.

Today I received a ''Draft Summons" by email stating I had an outstanding balance of R681.99

Vodacom's own collections contact number does not have anything on record for my number. This is unacceptable, and getting an actual person on the line to talk to about an issue is impossible.