New to platform but so far so good

I have Lost 15 bitcoins here which had been my savings. My experience so far has been when I deposit a bitcoin I win at first, but then soon after I would start to lose and noticed a pattern. This has happened 3-4 times to me. I play mostly the slots and I deposit one bitcoin and win a bit at first, and feel like the odds are with me, but then it goes on a losing streak. So I may deposit a few more coins but I continue to keep losing. When I first wrote this post I received a reply from Birwo saying they are provably fair but the rate at which I lost my coins concerned them and that they would refund me 2x my losses on this losing streak once they verified it. They told me if I supplied them with my ID they would take a look and process the refund. When I spoke to a support rep at Birwo, he argued with me about what I was told on here and said that the only thing he would be willing to do is give me a small bonus, half a bitcoin, but I needed to gamble 16 bitcoins to get the bonus. The site has been reported as not being provably fair on some forums on the web, even though they have a little side widget which says they are, I'm pretty sure it doesn't actually work. Just do a search and I would recommend to stay away. They have already been dishonest with their reply on here not delivering what they said.