It's clear even to you that there was no such agreement, but even to suggest it is to be an advocate for Russian imperialism. What you refer to as NATO expansion is really just the countries around Russia which had been invaded and held captive for 45 years until the collapse of the USSR banding together to defend themselves against another expansion of the Russian empire, just as western European countries had done when Russia invaded Europe at the end of WWII. For Russia to object to this tells us that Russia stilll considers them to be part of the Russian empire.