Before it gets worse, go to a dollar store or Home Depot and get one of those steel wire brushes about the size of a tooth brush and some Barge or equivalent glue. Brush both surfaces somewhat aggressively, until each is dull and obviously "Roughed up". Or use a dremel with a steel or brass wire brush, and carefully do the same.
Apply glue per instructions. Use a cheap small nylon paint brush (dollar store, bag of 20 for a buck type shit) to apply. Toss after (Not the shoes, the brush).