What does the stamp Refusal refusal to INA Section 217 in passport mean?

It means you were ineligible for entry under the visa waiver program. Without knowing more, it is difficult to assess why. There are a variety of reasons a person could be denied entry under ETSA. Some are more pronlemstic than others. You will need to actuall apply for a visa at the U.S. Embassy given you were refused entry. Before applying for a visa, speak to an experienced immigration attorney in detail about what happened to make sure there are no other issues.