Accidentally have 2 I-751 cases (mailed + online)

I originally submitted my first I-751 by mail and paid with a cashier’s check, not realizing that USCIS no longer accepts paper payments. After speaking with a USCIS agent, I was told the mailed application would likely be rejected, and because my green card is expiring soon, I decided to file a new I-751 online not wait for the rejected package.

Today I checked my USCIS account and noticed that I now have two active I-751 cases with different receipt numbers. Im unsure how to proceed. I also included a G-1145 form with my mailed application, and I received a text message today stating that the case was received.