Did tightening the belts help when you printed the key chain? The way you said that you pulled on the belt twice, sounds like you just pulled it with your hand or something. For both the x and y axis you can tighten the belts by loosening the clamp bolts on either the back of the extruder assembly or the bottom of the print bed, then pulling the belt through the clam and re-tightening the bolts. After that’s done the belts should have much less deflection when you push sideways on them.