Employers can claim for furloughed employees that were employed and on
their PAYE payroll on or before 19 March 2020. This means that the
employee must have been notified to HMRC through an RTI submission
notifying payment in respect of that employee on or before 19 March
If you made employees redundant, or they stopped working for you on or
after 28 February 2020, you can re-employ them, put them on furlough
and claim for their wages from the date on which you furloughed them
through the scheme. This applies to employees that were made redundant
or stopped working for you after 28 February, even if you do not
re-employ them until after 19 March. This applies as long as the
employee was on your payroll as at 28 February and had been notified
to HMRC on an RTI submission on or before 28 February 2020. This means
an RTI submission notifying payment in respect of that employee to
HMRC must have been made on or before 28 February 2020
However, the Coronavirus Job Retention Scheme is for employees on furlough who will have a job to return to. As you left voluntarily, and are not returning to that employer, you are probably not eligible for the CJRS, and your employer might be making a false declaration if they 're-employed' you solely for the purpose of the scheme.
If you are not eligible for furlough payments you should look at claiming benefits from DWP.