The scammers suggest they are from HMRC and either demand a payment, or suggest that a repayment will be made on providing bank details.
What to do if you think you've been targeted by tax refund and rebate scams:
Report all HMRC related phishing emails and bogus text messages to the HMRC. Even if you get the same or similar phishing email or text message often, email it to cGhpc2hpbmdAaG1yYy5nc2kuZ292LnVr and then delete it.
Do not open attachments or click any links in an email or text message, as they may contain malicious software or direct you to a bogus website.