What can I do to stop the sticker from peeling off?

To prevent stickers from peeling off, it is important to ensure that the surface to which they will be affixed is clean and dry. Apply the stickers in warmer ambient temperatures.
If you must apply them in cooler temperatures, gently warm the sticker using a hairdryer or another heat source to help strengthen the adhesive. After placing the sticker, it is advisable to gently press down for a few seconds to ensure better adhesion.