Engageent broke, what girl side can do.

I got engaged few months back as per of family consensus, but after talking to girl for 3-4 months i felt that she is not the right one for me. i lives in usa on work visa and she is in india. i felt that the only interest they have is to come to usa instead of marrying me.so that is why i broke the engagement. in engagement girl side gifted us some jewelry and other stuff which i am willing to return happily and also all the other expanses they had. but now the people from girl side are threatening my parents. they are saying all the bad words to them and cursing them and all. may i know if they can take any legal action against me? we did not married at all but i want to know what will be the consequences of it? can they harm my parents? i am hearing from some people that they can file a case upon the bases of false dowry statement nd all, can they do that? if yes then what would should i do in advance to stop all these? in short i want to know till what extent they can go? please advice