Account has been blocked and we don’t have enough information to recover it.

My cousins account got a virus, and she can sign in but not access her emails. Tried to recover it via Account Recovery but she doesn't have enough information about the account that is required there. Tried to send the security code to  her phone, but the service says that it's not working. She's does not write many letters, just gets her monthly  bills to her email so it's very essential for her to recover it.  If somebody could help us recover her account, we can give more information about it. At  least we'll try to give as much as we know.