What he said. The difference is that "suggesting" does not "cause" anything (such as a listing, or even a site review) to happen. It "enables" something (that is, finding a particular website at a presumably appropriate time) to happen "more efficiently." So a site review is likely (not certain, but likely) to happen "more quickly than it otherwise would have happened" -- but who knows how quickly a site would have been found if you had not suggested it?
So: No matter how many times you tried to submit, if at least one of the times you got a screen saying something like "Thank you for your suggestion....an editor will review it....bla bla bla...", then you've done all that is required, and all that is possible, to accomplish what site suggestions accomplish.
So, on the one hand, there is no cause for assuming your site has been repeatedly rejected; on the other hand, there is no reason for supposing that if it is ever to be accepted, it will be accepted soon.
But if you're depending on the ODP for site promotion, then ... it is safe to predict disappointment in both your near and remote future. A site review probably won't happen when you wish, and a site listing won't do as much for the site as you expect.
Also, as a side note, I would caution you to consider very very carefully what the concepts of "unique content" and "related sites" mean. For commercial sites, the "unique content" can be pretty well summarized in the question: who are you and what would you do for money? And for commercial sites, "relatedness" is pretty much that they all talk about various things the same persons would do for money).