Is this how MM works (ie MM rules broken)?

[apatia77]

So I wanted to buy a copy of World Of Warcraft Cataclysm from AtaRo.

I see j.col offering AtaRo £20 but he refuses as this is too low for him. So I offered AtaRo the money he would accept for it. I wait and wait and wait and then I see that the sale is completed. I check the feedback and I see that j.col got it so I assume he must have offered a higher price but not through the forum but via email.

Was this move against the MM rules?

 

[apatia77]

It's not because I didn't get it, it's the principle of it, if someone offers you the price you want you sell it to that person you don't go behind someone's back to get an extra £1.