Baffled by Telkom and Open Serve responsibilities

Very confused about Telkom and its link to Open Serve. Have an issue with my internet strength suddenly being of intermittent quality. The line was found to drop intermitently at first. When the problem persisted I logged a fault requesting that my router get checked. Suddenly I got an sms that the problem was resolved which was baffling as no technition came to check the router. So I logged a fault again. A chap from open serve phoned and I explained the problem. When I asked him to email me what I may be charged for if they come out., he said it was " complicated" and refused to do so. Looks like Telkom and Open Serve are separate entities. Telkom provided the router so who will check it?