User Activity

Hey guys..Is it possible for me to hide my contact no's from sellers? Because everytime i'm not satisfied with product i leave neutral or negative feedback..And these sellers keep making pesky calls every 2 hrs asking me to change feedback..
Hey guys i am new ebay user,I usually go to store to buy shirts,I foolishly ordered a XL size shirt worth 450/- instead of buying a 400/- Please can anyone tell me how i can cancel the order.I really dont want that shirt i only ordered it 10 mins ago...