Financial questions that need an answer

Hello, someone has prefabricated 7 offers on my domain study for sale. The price started at $100 now he is up to 2,000..I told him that my FIANL offer is 7,000..Even though I only had the study listed at $500 origianlly. I received an offer of 6000 so thats why I had to raise the amount. But this guy doesnt understand and he KEEPS on putting low offers in..What do I do now> This is my first time for this. DO I let his offer expire fpor the 2,000 or just tell him again I got a higher offer ??

Thanks for helping me, I apprecaite it!!