Your bee may be a honey bee. Honey bees build large colonies inside buildings and so they need a void about eighteen inches (half a metre) cubed; chimneys are a favourite spot. Bee colonies in buildings are notoriously difficult to remove, it doesn't matter if they have been there five hours or five years. Beekeepers are loathed to try removal, it's a very difficult job!
If you have them fumigated the Pest Control Operative is duty bound by law to block the entrance to stop other bee colonies robbing the honey from the comb inside the colony. Honey is hydroscopic and will expand as it absorbs water, dripping out of the comb into your building. You cannot remove honey from the fabric of a building, you can't paint or paper over it, your property will be seriously damaged!
Many people live for years with bees in their property but if you want them gone, here's what to do.