When this came up last year on a news report, the “government” said the plates were guaranteed for five years (where was stated when we bought the plates) You are on the hook for new plates at full cost after five years.
Ontario’s plates are an embarrassment! Here and outside the province. I spent many hours working on that Ontario logo only to be attached to garbage that we paid for and no responsibility by the firm that made them.
Mine were about to go and I coated them with polyurethane, probably three coats it helped.