You should speak with an immigration lawyer. You do not want to do anything that could delay or cause problems for your pending application.
Any comments offered are not intended as legal advice. This attorney does not know the specifics of the particular case sufficiently to offer legal advice. You should hire a lawyer who can evaluate the details of your specific situation before offering advice.
You should make an InfoPass appointment to try to determine the cause of the delay. Take all of you documentation with you and receipts from USCIS.
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The statement above is general in nature and does not constitute legal advice, as not all the facts are known. You should retain an attorney to review all the facts specific to your case in order to receive advise specific to your case. The statement above does not create an attorney/client relationship. Answers on Avvo can only be general ones, as specific answers would require knowledge of all the facts. As such, they may or may not apply to the question.
I'm assuming that you filed an I-539 to change status to F-1 from B-2, and that this was filed before the B-2 expired.
An InfoPass appointment may be a good way to force an answer. You might also go to the office of a local Representative from your district and ask for assistance.
Then, when you figure out what is actually going on, speak with an attorney - you may have some serious difficulties depending on where this case stands now, impacting your ability to reenter if you leave.