MyTNS.com, online survey website

Have been with mysurvey.com (previously tns) for many years now, and up until recently was fairly happy with them. However, a while ago over 2000 points disappeared from my account for no reason and with no explanation. I have emailed them 9 times in total now, and also sent a letter, as have heard no reponse and my points are still missing. This is most frustrating as had been saving the points for a xmas gift, but can no longer get it now. In one of the most recent emails to them I asked for info on who to complain to regarding the situation and lack of response, but of course I received no response to that too.
I feel increasingly angry and let down by tns for this, at the end of the day I did the work for them by spending a vast amount of time filling surveys, and now have nothing to show for it. I did not agree to work for nothing but that appears to be what I did for the last year as those points have disappeared. Some kind of response from tns would have made it all so much better but to ignore me and the time I have spent trying to contact them is yet another slap in the face.
Due this i will be telling family and friends to stay away, and in particular people from companies who comission tns to survey for them.