Apple won’t charge me for in app purchases after months, why and how to fix it?

In February of this year, i purchased in game currency for a game on my iphone using apple pay. After a few days i started getting charged for the purchase but didn’t have money left to pay it, it’s now been a few months and even when i had money apple has not charged me. It says it’s been pending for months and last time i was charged was in march. I need help as i cannot update or download new apps, please help? anyway to force the charge would be appreciated.