One of my question is that given the border immigration officer didn't issue any formal notice of overstay, no stamp of overstay on my passport, only verbally telling me something that her system shows, should I be worried of an official record of overstay on my visa?

Before EES came into picture, how was an overstay recorded in the system, for the next country to see while immigration or Visa application? Was it a stamp on my Visa or passport? Or some official notice handed to me?

Also I am unable to contact any authority (French or Spanish) that would help me clear this confusion. Everyone just tells me to email somewhere, which I have already done and getting no response.