Bad Service From Discovery

We called on Saturday 28th September to log a call regarding blocked drains. Discovery sent out One call plumbers to come and access & address the problem. The plumber arrived, wasn't here for very long, didn't have any proper tools or equipment as previous plumbers that were procured by Discovery. Shortly after arriving he told us the problem is sorted, we were out the remainder of the day & therefore didn't make use of the sink etc until the next morning, only to realise that the drains are still blocked and that the issue was in fact not sorted. To mention a very important fact, the plumber didn't give us any paperwork, job card or reference number and neither did Discovery. To point out also that until today when I called there was no history of a call number ever being logged. Which is not only unprofessional but the incorrect protocol to follow. After asking Discovery, and the lady on the phone confirming that they not send One call plumbers again, they were sent again today. For some reason they could not come last night. So how did they perceive this as an emergency? Today the men arrived after 10am, were here for a short period and told my children that they need to leave to get equipment to unblock the drain. After a while they returned & fiddled around in the pipes, made the bath filthy, and said that they can't reach the blockage and that they would need to get other machinery or dig up the pipes to find the blockage. Apparently it's something hard ... that is just interesting that they can say it's something hard but can't get it out. When they left, they gave the kids a piece of paper with our address on. My wife took it upon herself to call the insurance when she heard them leaving shortly after they arrived because they did not work the entire time that they were here, and can't charge Discovery or us for that. I called Discovery later on to find out exaclty what is happening as strangers enter my property but I have no details of what the cause or solution of the emergency is. Interesting enough, the people in the call centre told me that no calls had been logged on their system, so now i'm thinking there are underhanded things happening. This means I have no idea what the service provider feedback is or what they are charging for. My broker also got involved as foul play had been suspected from their side also. When I got home, my children told me that we apparently can't use any of the facilities as everything is blocked....now tell me how after a plumber has been here, that the situation could be worse then before they arrived. So what did they actually do? I once again called Discovery, spoke to a gentleman in the call centre whom was not helpful at all, I asked for his manager .... now this Simon guy had an even worse attitude & still could not assist. So the result now is that it's 4 days later & we are not only in a worse situation, but the soure of the problem isn't solved. My question is this, I pay Discovery a substantial amount to receive the good service that they are advertising. I want someone of higher rank, that knows what they are doing to contact me asap so that this issue can be resolved.