You can certainly decide not to sell your home; however, be aware that if a Realtor has brought you a ready and willing buyer, and an offer you agreed to, you may be liable for a commission. You need to speak with a Real Estate Attorney to discuss your legal ramifications.
It depends. Talk to your Realtor. However, you may still owe commissions and you will have to deal with the buyer. The buyer can sue you for specific performance, which means they can "make" you sell it to them. Maybe you should get an attorney.
Hi Morales, a contract is a legally binding document. You want to read through it carefully and consult an attorney to see what options, if any, you have. Please also keep in mind that the buyer has already invested emotionally and, depending on what stage of the contract you are in, financially. Best of luck.