They are politely sending you on your way. Don't be discouraged. Try other agencies. Most have specific types they are looking for. If you are not right for any agency, talk to some professionals to find out if you are taking the right approach.
Some girls refuse to cut their hair, lose weight or make other alterations in their appearance.
They will never make it in this industry. It is all about change. Agencies make money when you do. Avoid agencies that want money up front to represent you. You must be prepared to invest in your career.