Defective and dangerous net

We contacted H2O for a pool net because we have 2 kids under 7, and we want them to be able to have the run of the back yard without worrying.

Initially the response was great - fast and professional. Then we had to put down an 80% deposit before he could have the net made. We paid the deposit and waited. The time he gave for the net to be made came and went, and he didn't give us any indication what was going on. So we contacted him and the runaround began - the net will be ready in 2 days, then tomorrow, then still tomorrow...

A week later he finally arrived with the net to install it. He installs it and when I queried why it seemed loose he said that's the best that can be done.

A few days later my son and I decide to go for a swim, so I remove the net for the first time. Every single one of the safety anchors that hold the net to the bricks came off. I ended up standing there with two hands full of safety anchors and a net that can't be put over the pool after our swim. To make it worse, the tension rope was so slack that my 6 y/o could remove it, after which he could easily remove the rest of the anchors - exactly the thing a net is supposed to prevent!

I messaged H2O and requested my money back as this is clearly a defective product. Had one anchor come loose I could understand and have it fixed, but this was 100% failure which I haven't heard of in my life. The net is completely useless as a safety device. He initially refused, then agreed, but since then hasn't paid a cent back even though I have a useless net and children in danger of drowning.