Identity theft for sure. It was pretty common a few years ago, but the IRS has implemented safeguards that have cut down on it. Someone gets your info and files a tax return with phony documents claiming a large refund early in tax season before the IRS has the documents to verify the amount of withholding. The IRS has no way to verify it is actually your bank account. Here is a link to the IRS website with More information
https://www.irs.gov/newsroom/taxpaye...identity-theft
You need to complete form 14039. Unfortunately it will be a real headache to straighten it out, especially since the IRS is working with limited staff due to the Corona Virus.