It seems there is limited publicly available information specifically about the "Cosmic Trade" platform and the validity of the referral code "NDUMTM" for trading fee discounts.

Here are a few things to keep in mind and steps you can take to verify this offer:

• Verify the Platform Name: Double-check the exact spelling of the app or exchange name (e.g., Cosmis Trade, Cosmic Crypto, or a similar variant). Sometimes a slight difference in spelling can lead you to the wrong platform.
• Look for the Referral Field: If you have already installed the app, look for a section labeled "Invite Friends," "Referral Code," or "Promo Code" usually found in the profile or wallet section of the app.
• Check Official Sources: Look for the official website or verified social media pages of the exchange. Legitimate exchanges usually list ongoing promotions or partner programs there. Be cautious of codes shared on unverified third-party forums.
• Read the Terms: If the code is accepted, check if the 10% discount applies to the "maker/taker" fee or only to specific trading pairs or account types.

If the code doesn't work, it might have expired or be limited to specific user regions. You might also contact their customer support directly to ask about current referral benefits.