Here, in my geographic area, the second payments were sent in form of EIP debit cards.  

Many clients, including some family memberS  (plural), threw away their cards, thinking it was some kind of scam - it required registration by SSN etc.

I once thought the second EIP payments were all sent by debit cards, but one evening I sat (sipping bourbon) corrected.  Lost the bet to a client in Arizona.  Lucky for me, I didn't give odds.

There used to be an 800 number to call to report stolen EIP cards or to check the card status, and - at one point - it would give out the dollar amount on the card and whether it was cashed, once the caller was authenticated.  A few clients replaced their cards (or their aging parents') simply by calling the number.  The replacement cards arrived within  a few weeks. 

I prepared a quick reasonableness test on the Payment I and II amounts before finalizing clients' 2020 returns (because I have their 2018 and 2019 AGI info.  Very relevant.)  Spent too much time on that issue (especially showing how the aging clients how to get the replacement cards) though.  In all cases (based on a rather small sample population), the second payments (debit cards) were the culprit.

Hope this helps.  Perhaps your client could revive his/her/their $333 debit card.  If so, buy me a drink....