your urgency is never uscis's urgency...calling will not do much and you just need to be patient. this highlights the reason you use an attorney because of the knowledge an attorney possesses about the immigration process and what to do on the case, the RFE could have been avoided and would have saved you a lot of time and not put you in this predicament of potentially failing to register and/or losing money. Saving money by not using an attorney often will cost more in the end. Good luck with the case.
Please be advised this answer is for informational purposes only and no attorney-client relationship has been formed. You should also see a local attorney for legal advise before acting on any of the statements given to you online as there may be aspects of your case that are not obvious by the question asked online.