Purchasing

Hello and good evening. First off let me say how much I love this game. I literally sign in and play it every day. Now, I'm not rich by any means, but I do spend around $200 a month on various purchases through the portal. My one complaint is that in the last 4 months or so, I've spent around $700-$800 on purchases that have different pulls attached. I realize it's a gamble, but I have not got one new superstar in any of those pulls. All I get is shards to stars I already have. Is there anything you can do to up the odds for people who spend and spend, even though they probably shouldn't, and get nothing for it? Thank you for your time, and again, great game.