Returns and complaints

You have 30 days from receiving the book to withdraw from the contract without giving a reason — we voluntarily extend the statutory 14 days to 30.

Simply send a statement to junior@aisigma.pro within that period. You may use the template below, but it is not obligatory.

Return the book without undue delay, no later than 14 days after your statement, to: [FILL IN: returns address]. You bear the direct cost of the return.

We will refund all payments received, including the cheapest delivery option we offer, within 14 days of receiving your statement — we may withhold the refund until we receive the book or proof of its dispatch. The refund uses the same payment method as the purchase.

The returned book must not show signs of use beyond examining it; you are liable for any diminished value resulting from handling beyond what is necessary to establish its nature and characteristics.

We deliver the file right after payment (or on release day) — with your express consent given at checkout. Once you start downloading, the right to withdraw from a contract for digital content expires (Art. 38(13) of the Polish Consumer Rights Act, implementing EU law).

As long as you have not downloaded the file, you can cancel within 14 days of purchase: write to junior@aisigma.pro with your order number and we will refund the full amount by the same payment method, within 14 days at the latest. We can see whether the file was downloaded.

After downloading, a refund is due when the file is defective — it does not open, is incomplete or does not match the description. We then fix it or refund you. On refund we revoke access to the file and it disappears from My books.

Every copy is marked with your name and an invisible fingerprint. The file is for your own use: read and listen on all your devices, but do not share it further.

“I hereby withdraw from the contract of sale of the book [title]. Order number: [TZ-XXXXXXXX]. Received on: [date]. Name: [full name]. Address: [address].”

If the book is defective — a printing error, damaged pages, transport damage — write to junior@aisigma.pro with your order number, a description and photos if possible.

We handle complaints within 14 days. If the complaint is justified, we will print and ship a new copy at our cost or, if you prefer, refund your payment.