Fenix 5x battery fault suspect

My 5x comes on when attached to the charger. If I leave the watch on charge for an hour or so the meter shows 100%. However as soon as the charger is removed it switches off. It wont come on at all. So, am I to assume the battery has just died on its ass? I am out of warranty. Does anyone know my options? Can i get it repaired, officially through GArmin. I don't fancy a back street repair. Would love a Garmin employee to hit me up, appreciate its between the holidays though. Many thanks