Standard bank Insurance incompetence

I have an insurance on my home with Standard Bank for the last 11 years (linked to my loan). I have a problem with my geyser and have been trying to log a call with Standard Bank for the last two weeks and they are not returning my calls at all. I have sent an email, but they have not adhered to their 48 hours turn-around time to date. I am still having issues and am left without option but to source a plumber on my own. So why do I have an insurer who is not contactable nor are they not responding to my calls? Who will then pick up the costs if I source the plumber and what is my recourse for this lack of response?