I completed the purchase at dispenser, but "CLICK HERE TO ACCEPT GIFTS" doesn't disappear.
Could you help?

I think you bought 24 CS:GOs from me and the "Waiting for Gift Accept" is still stucked. I and many others are having this issue too. It's a Steam Bug / Glitch, only thing you can do is to wait and it will fixed by itself. This can take up to 12 hours like it took for me. It's annoying but I already made a thread about this issue and Joto is looking into it. Cheers :)