Hey there, I've rarely ever heard of someone not receiving their item after they purchased it, firstly after purchasing your item from the store you need to make sure that you put your in-game name correctly, I recommend waiting at least a couple hours while being 'ONLINE' on manacube till you receive your items. If this doesn't work then it might have been a small issue on the payment/server-side so simply make a ticket here - https://manacube.com/support/ specifying the issue, etc and we should be able to check if the payment actually went through, etc. on behalf of the ManaCube staff team, I guarantee you that ManaCube would certainly not scam their player base and we always try our best to solve situations like these as efficiently as possible.
I'm sorry this happened to you! Just because you didn't receive an item doesn't mean the whole server is a scam. Was your inventory full at the time by any chance? Did you not click the "Yes, I read the terms and conditions" button? Whatever the reason, if the order went through and Dacon received the money then they can easily give you your item. Just go to https://manacube.com/support/ like TheProTroller said.