Half is due by the end of 2021. The other half is due by the end of 2022.
Tell us about this notice. Issued by SS or IRS? Does it show a due date? Does it list the amount due now, in full, or both?
This is the first post I've seen for it.
Your client would not have deferred their entire amount.
"Level Up" is a gaming function, not a real life function.