What was the original check-in time of the unit? Did you request for an earlier check-in? Quite possibly there was guests booked before you and they need that time to clean the unit. Standard check-in and check out times are in @ 10-11AM and out @ 3-4PM.

This is a very reasonable unfortunate situation that a host faces but by no means should you cancel the booking because of this or find alternative accommodations. This is Airbnb and not a hotel that offers 24HR concierge service. This is a common person that has common circumstances that could arise during the day that would delay your check-in a few hours. Why must you check-in at 2PM and not 5PM? Can you not kill 3 hours by going to a coffee shop/go for lunch/ or browse Reddit and post discussion threads for a few hours? Have you arranged an important meeting to take during those hours inside of the unit? Are you harbouring Edward Snowden? I am not sure why you have such desperation for being checked in late. These are the small imperfections you may face when booking an Airbnb and you should realize this.