used my grandma to steal money

My grandma is very old and some people take advantage of such people. Like this company which called her up and asked for her credit card just for their "database" where they would keep it, and they said they wanted to help her sell her timeshare. She believed everything this "sweet voice" said to her, and provided the number. So they scammed her until the last dime she had! I will take them to court if it will be needed to get her money back!