There are for sale by owner web sites but the best way to sell a house remains with a Realtor. I'm not just saying it because I am a Realtor but a good Realtor can market your house and get it sold. Statistics show that 94% of FSBO's eventually list with a Realtor and Realtors get 14% more money for sellers.
If you put an inspection contingency in your offer and followed the dates that were in the contingency then here in Massachusetts they are required to give you back your offer deposit. Call your agent then the broker who runs the office you used as your buyer and ultimately the local Real Estate Board if you need to fight to get the deposit back.
The pre-approval process varies a great deal from agent to agent. If you get a good mortgage person they will be able to get you pre-approved if you qualify. They may do a more extensive process for you requiring more documentation. For example,...I had a self employed restauranteur and they did a pre-approval that took a few days and went through a limited underwriting process. So find a good experienced broker who is able to sell multiple products.
In Massachusetts 6 pictures are required before your listing is sent out to other websites.