Please do not submit many times.
There are some sites the ODP does not ever list, no matter how many or how few times they are suggested.
There are other sites that are about topics that may be well served already, or may not have much surfer interest, or are spammed so badly that volunteers do not like to research them.
By reading the editors' guidelines, knowing your site and the competition, it should be easy to figure out which possibility is most likely.