No service from Telkom

We are really having a serious problem with a telkom phone. The phone belongs to an elderly lady and is right next to her bed should she need to make an call as she has difficulty walking. The last couple of weeks the phone makes a terrible noise when not in use. We have reported this phone numerous times to Telkom when we do we get a message that they have attended to the problem and it is solved(which is not at all the case) or we are left without any response at all. This problem needs attention urgently as the lady can not be left without a phone in case of an emergency but the phone makes such a noise day or night that she dont get any rest