Apparently there's no option from the dashboard if you want to see the requesters who rejected you from the day you started turking (you can only see it from the "HITs Submitted Within the Last 45 Days"). My rejection rate has increased dramatically cos of "user453" and "Tagcow" so I thought of checking every requester who has rejected me from the beginning so after going through the site of mturk I couldn't find a way. I guess this is a very important thing mturk must look into.