Cancel my telkom line

I Cancelled my telkom line on March 23 2021. They sent me a reference no. They did`nt cancel the line and they keep on sending me a bill. I`ve tried numerous times to phone them but it`s a mission. When I eventually came through the operator told me "we are offline, phone back later.. They clear the bill and cancel the !! It`s easy. P. du Preez