Information regarding joining a company

[sun123011]

Hi,

I am having an offer of company A in US, but i refused to join them and just dropped a mail, after few days due to some reason i again wanted to join them so i called and they were ok with my joining on the same position but now i have got another offer and i wanted to opt that and not of company A.

Please suggest will there be any problem if i refuse company A second time for not joining them,although i have not signed any agreement, have just filled few of their online joining forms related to joining.