after reading this thread i realized that many czechs (moravians?) (mis)pronounce "ne" with a glottal stop - just like the name "Ned", only swap the d for a glottal stop - maybe it can be easier for you that way? or it can even become nee with a glottal stop between the two e's - perhaps akin to saying "nope" in english.
Yes, Moravians do that. I'm not sure about Bohemians. We don't do it because it's easier to pronounce that way (it's not) but it is a more colloquial way to say "no". It could probably be compared to the English "nope". I think this is common all over the country but I could be wrong. The "double ne" is a way to emphasize "no".