Getting a refund is an option you choose at the start of a contest. If you forgo this option, you may attract more designers (because they can be certain you will pay somebody for a design).

If you choose the path with a refund, you only guarantee payment at the second stage where you choose finalists. If you don't select any finalists to work with, you can cancel the contest and get a refund.

If you guarantee the prize or have already selected the winner, you will not be reimbursed. They only reimburse if you avoided these two actions. When you reject the designs, they will likely pressure you into accepting something, but do not do it. If you're not satisfied with the design, according to their rules you will get reimbursed. My problem is that after awarding the winner, the designer Alex_82 told me I owed more money for the images which I refused since the agreement with 99designs was for a set price. In the end, 99designs sided with the designer and I ended up with designs I did not want (they were off of free images) and of low quality. I also could do nothing with the design because I would have had to purchase additional software. For my money, I got nothing.

Yes, they will reimburse you and they did reimburse me so that is one positive thing about their company.