As an international student, you might be contacted by a scammer pretending to be the police, home office or someone asking about your visa, saying they urgently need money or something bad could happen. They might say a family member is in custody and needs to be bailed out, or that you need to make a payment or you might be deported. They will put pressure on you to pay quickly to avoid consequences, and they might have gained information about you through your social media to make it more believable. More information here.