Evisa

I am soo confused with the Evisa process. I've got a evisa online account, when i first made the evisa account, i linked it to my BRP (with ILRs) cuz that's the most common sense thing to do but at that time my BRP has already expired like the physical card but the status remained the same, I travelled with it in summer this year, when I came back and went through UK custom, the lady said my BRP card has expired but ILR status remained and advised me to change the evisa link to my passport instead, but I dont own a british passport and the passport im currently holding have no document to prove or to state that I have the ILR status like how the older generation used to have a stamp or sticker in their passport. Is anyone experiencing the same situation pls any help would be appreciated.