Sometimes yes/sometimes no means no to them - careful with that one.
The "I don't know, what do YOU think" is a classic, though. If they ARE bold enough to say you are not, make sure you don't agree with them. Keep asking questions:
"Really, why not?"
blahblahblah
"But why does that make you think I'm not a JW?"
blahblahblah
"But based on what direction have you made that connection?"
blahblahblah
"But how do you know that is accurate divine direction?"
{angry}BLAHBLAHBLAHBLAH
"But why does that make you think I'm not a JW?"
BLAHBLAHBLAHBLAH
"But based on what direction have you made that connection?"
lololol, etc.