How do i prevent change of address with usps?

I have recently become a victim of a phishing scam, and I am concerned that someone might attempt to try to "change my address" in order to receive my mail at another address. I have already taken care of the other security issues (i.e. social security, banking, credit bureaus, etc.); however, I was trying to see if there was some type of form I could fill out through usps.com in regards to taking care of it now...(they are closed on Sundays). Has anyone ever had this happen to them? At the moment, this is just an umption; nothing has happened yet, but I feel it is very necessary to take the proper precautions. Luckily, I've pretty much taken care of everything quite promptly. Please, only respond with respectfuly and "positive" feedback. I truly appreciate any istance you all could give!