I have submitted all problem sets except one (7). The problem is that the problem set I have not submitted has been graded 1 and there in one problem set (4) which I have submitted but has not been graded for a month now. What should i do?
For the one that's not graded, I would suggest that you resubmit it. You can always resubmit a pset - only the last submission will be counted. (Be sure to submit the entire assignment, not just any one part that you want to resubmit.)
For the one that you say was graded but not submitted, you should be able to download whatever it thinks was submitted. You might find that you forgot, or at least get a clue what happened. Again, you can resubmit, so when you actually finish the assignment, you can submit your work and override whatever is in the system, wherever it came from.
I'm not exactly sure how it would play out if you submit all other assignments and still want to submit your own psets. It might consider the class finished for you, so you might want to hold back one unsubmitted set until everything else is submitted or resubmitted.
If there are still problems, you should contact staff directly, or at least one of the moderators here, like @curiouskiwi for further assistance. (btw, I am not a member of staff or a moderator.)
IF this answers your question, please click on the check mark to accept. Let's keep up on forum maintenance. ;-)