Redundancy where no tax paid

I was recently made redundant, at the end of my maternity leave. I didn't pay any tax on my lump sum as my credits covered it.
My question is do I still put a top slicing relief in or is there another form I can put in to claim tax back for the year 2013 as I would have been unpaid since half the year due to unpaid maternity leave, so would presume I am due some credits back. Thanks

If you did not pay tax you can't get tax refunded. Tax credits are not refundable.

You wouldn't pay tax if its below statutory redundancy amount or your tax free allowance for year.