Yeah, I've seen those ads on TV and YouTube. They seem kind of scammy to me.
Are you an employee? FFCRA says your employer must give you extra sick leave. If you get sick leave, it's still taxable income on your W-2. If you didn't get sick leave, there is nothing you can file on your return, you would have to complain about your employer to your state labor regulator.
Are you an employer? Did you pay sick leave under the FFCRA to your employees? If so, you may be able to claim a credit for those sick leave wages on your business tax return (schedule C, or form 1120-S or form 1095, depending on what kind of business you had.). Here is the IRS FAQ page for the credit.
https://www.irs.gov/newsroom/tax-credits-for-paid-leave-under-the-families-first-coronavirus-respons...
Yes, you would have to file an amended 2020 and 2021 return to claim the credit if you did not claim it at the time. The deadline to file an amended 2020 return is May 17, 2024 for most taxpayers.
If you were not an employer, or if you were an employer but you did not pay sick leave under the FFCRA, you may not be dealing with an honest attorney.