Telkom consists of two separate entities - Telkom Mobile (GPRS) and Telkom Landline for ADSL/VDSL (fibre) services, I assume your survey is in regard of the latter? Secondly, the survey is not about billing disputes and the like which has nothing to do with fibre service related user...
If I would transfer from ADSL copperwire to VDSL fibre both at Telkom would I then be an ADSL subscriber loss? I am, afterall, still a Telkom client.
Makes your Telkom ADSL subscriber-losses figure non-sensical seeing there is an ongoing and concerted effort to migrate them to fibre.