If they send you gifts in other than their festivals, it is OK to accept it. But if you send you gifts in their feasts, if these gifts are part of their feasts, it is not permissible to accept as in the case of Easter eggs, for example. Dining in their homes and eating their food is accepted if they are Christians or Jews. If they are not, you can’t eat their meat as it is forbidden and considered to be dead meat. Socializing with these people has to be with the intention of calling them to Islam.