Global Test Market Lightspeed Research won't respond to emails about unpaid reward from Aug 25/16 Bellevue Washington

in the past 5+ years i've rec'd many cash rewards from GTM via PayPal -- the payments have always been reliable (if slow);

Aug 25th, 2016 i requested a $50 cheque (rather than PP) to be sent to me, which i have yet to receive; have checked in my PP acct and it wasn't deposited there, either;

i've tried to contact them several times, but have only rec'd one response, which said to check their website for my request # -- i did this, but it was marked "solved", which it certainly isn't; still no response to my replies to this email;

i've checked my GTM acct, and the points were, indeed, removed from my total, but i still have not rec'd either the money or any explanation;

if i managed to screw up my original request for a check, could they not just replace the points into my GTM acct, and i could continue to do their surveys, which they continue to send me regularly????

grateful for any assistance you can give me!!