Help, my bra bands are riding up from the backside?

I have been trying on a 36C bra and my bands are riding up from the backside. I'm trying to push the straps up from front to to my shoulders and behind but it's making the cups too tight and makes the back band tight and it rides up as well. I've tried pushing the straps down as most as I can from the front and it frees up my cups comfortably but the back band still rides up and it's visible. It's only improving if I tighten up the hooks that keeps the band together on the backside. But, even in this position the front hook that keeps the cups together from the front doesn't stay on my skin but 1 inch away from it. Does that mean I should go for a bigger cup like from 36C to 36D or something else ?