Can I Claim a Deduction to my Lump Sum Pension Payout Against my Income?

I recently quit a union job with a pension where it made sense to cash out my pension rather than let it mature. Before quitting I was on education leave where my pension contributions were deferred with the intention that when I come back to work I repay the back amount. I quit before this happened so when I cashed out my pension there was a deduction to my total payout that reflected the owed amount.

I just received my T4A forms for the pension payout and the payment amount in box 18 reflects the value before my deduction was taken.

I contacted my pension fund and they told me that the T4A must reflect the value of the pension they paid out, not the value minus the deduction. In rough numbers the gross value was ~$13,000.00 with a deduction of ~$3,000.00 pre-tax. But when they paid out my lump sum, the taxes taken at the time reflected the total after deduction. This has resulted in my owing the CRA a lot in taxes instead of getting a return.

My question then is, can I claim the deduction amount against my earned income? Either as a lump sum pension contribution or a reduction in income in the last year?