Bad winning odds

I have spent 100s of 1000s in sporting bet recently and did not get anything back. They have rigged it in such a way that its so difficult to win. There are way too many bonus deals but you can't actually win most of the time. I will not be using them again. In the past 2 months I have put in so much and couldn't even get up to R5000 in winnings and then it was all gone. I thought to try again but everytime I deposit my funds get depleted so quickly. To think that because I've put in so much I'd at least be given a small portion of what I put in back, but that was not the case.