I have done a lot of work for one guy - 5 articles which I put a lot of effort into. They are completely original and good quality (believe me I know that). And he has neither accepted nor rejected them. They just sit there. OK - it is only $10 worth of articles - but a couple of hours + of work and really annoying. Is there anything I can do? It puts me off the whole thing.
If a month has passed since you submitted your articles, than you must contact the requestor and try to find out. I think there is an auto approval system, where articles get approved after a month if the requestor does not approve or reject them. So check it out.
If more than 31 days have passed having you submitted the HIT, then you must probably contact mturk via their "Contact Us" link since all the HITs which are still pending to get approved or rejected by the Requester get auto-approved. I know this as I'd once asked Mturk about it and got aforementioned kind of reply.