Help center
How can we
help?
Most questions are covered below. If yours isn't, write to us — a person reads every email.
Topics
Browse by topic.
Orders & shipping
Track an order, update an address, or change a delivery date.
Read moreReturns
Start a return for an unopened cube within 30 days.
Read moreShipping options
Delivery times, rates, and international shipping.
Read moreGameplay
How 3D Sudoku works and how the hint engine helps.
Open gameBilling & subscriptions
Manage your plan, see receipts, or update payment.
Read moreContact support
Stuck on something? We answer our own email.
Read moreCommon questions
Plainly answered.
- How long does shipping take?
- Standard US shipping is 3–5 business days. Expedited is 1–2 business days. International varies — usually 7–14 business days.
- Can I add a personal note to a gift?
- Yes — there's a notes field at checkout. We handwrite gift notes on the inside cover of the box.
- Are the cubes waterproof?
- They're premium cardstock with a soft matte finish. Splashes are fine; submerging is not.
- How do I redeem a puzzle code from a card?
- Sign in and visit Puzzles → Add Puzzle. The code is on the back of every card.
Still stuck?
Email support@zudocube.com and we'll get back to you within one business day.