But they didn't say that anywhere BEFORE sending my coins.
Are you absolutely sure that they didn't mention anywhere on the site what's the minimum amount that are willing to mix? Somehow I doubt that.
Anywhere on their site??
If it is a fine print hidden somewhere, or in their terms and conditions or policy of 50 pages instead of boldly in front of you when you are paying would... that be a "hey! Its your fault. They told you"...?
I remember...a) not seeing it and b) actively looking for it thinking stupid me didn't notice but still not seeing it. And no, I did not comb through their site and terms and conditions to search or any indications that I would be had. I expected a legit business to make make sure to make such things clear from the git go. The only reason you wouldn't is to scam people in some shape or for and to some extent.