Impossible to cancel DSL service

Try to cancel DSL service as switched to Vox fibre. Phone 10210. Eventually get a consultant...after many questions, etc, am told to try the telkom website of phone 10213#1#5. The phone just has a recording that tells me to register on portal. Try to register on the portal, get emailled an OTP...type in the OTP and the form submission is disabled. So...is it impossible to cancel Telkom services?