1. Your Boom products disappear from the Boom Learning Store.

2. TpT purchasers who attempt to redeem after your Store closes will get an error message.

3. Decks previously sold and redeemed remain available to the buyers.

As a practical matter, delist on TpT well in advance of any plans to let your Boom Learning account expire to minimize frustrated customers. Also warn TpT customer that they need to redeem before a certain date (your Boom Learning  expiration date).