EPM7128LC84-7N CANNOT BE ACCESSED

You first need to be careful with your nomenclature.

EPM7128LC... devices are NOT JTAG programmable devices. They must be programmed on a 3rd party parallel programmer.

EPM7128SLC... (note the 'S') are JTAG programmable devices, but they can be programmed to disable the JTAG pins and use as I/O pins.

I am assuming your use of the non-S part number was just a typo on your part.

But the parts you sourced from eBay who actually knows if they are good, bad, or counterfeit?
Maybe your seller knows, or maybe not.
Almost invariably parts this old are pulls from equipment.

They could be good parts but were programmed to disable the JTAG interface in their past application, to mimic non-JTAG parts.
If so, you need a 3rd party programmer to erase the programming and reenable the JTAG interface.

And the -N suffix just means it is in a Pb-free package. The internal part is the same, -N or not.