As @cavedog has pointed out above, I think where you went awry was at point # 1. : "I inform them that I already have one".
Pure DSL / Pureconnect is a new product. The process must be followed. Your old line was telkom's: Your new one would be Openserve's. By turning away the Openserve techs for their initial site visit you threw a spanner in the works (so to speak).
Good luck getting it sorted.
Indeed they are definitely separate services.
Old one called copper connect needs to have an active voice service.
New one called Pure connect does not have to have voice.
They have different pricing and structures on how they operate and on the openserve ordering portal they are very different.