How to remove MDM profile from MacBook Pro

Hi there, I bought used MacBook Pro. Someday I erased it and installed a new OS, but receive window with login of US college. I installed old OS with usb stick and now it works, but usually I see the window to setup the college profile. So, I contacted with college with my problem, tell them my serial number and they told me that they removed my device from their MDM, but I still receive the windows to setup college profile. Do I need to try erase my laptop again, will it work?

thanks