Why is the date for my fiber connection in January?

Ordered TV + 1gb fiber several weeks ago and had a mid-December date. Stopped by KPN store and was advised to cancel so they could try placing order for better instal date. Upon doing so, store received a mid-January date. I already have fiber inside my house, so why the far out date? In the meantime we switched our cellular over to KPN from Vodafone to get better 5g reception, but we keep hitting our daily 10gb limit. Help!