Email [email protected] and we will sort out a replacement part. We do not have a spare-parts shop page, so it goes through support.
Identify the part first. The parts come on lettered sprues, and every part has a code made up of that letter and a number — A01 to A14, B01 to B27, C01 to C31, and D01 to D10. So the part you want is something like B26 or C07. You will find the code against your part in the Components PDF, which is the first download on the Mars Rover build guide page. If you cannot match it, a clear photo of the part works just as well. The guide is on our Mars Rover build guide page. If you cannot find the code, a clear photo of the part next to something for scale works just as well.
What to send us
Your order number
The part code (for example B26), or a photo of the part
What happened to it
A photo of the board or assembly it fits into, if it is an electronic part
Whether you pay for it depends on what happened, and it matches our warranty:
Missing from the box: free. That is our packing error.
Genuinely defective: free replacement under the warranty.
Broken in use or assembly — dropped, mis-assembled, wired the wrong way, overheated or forced: we can still send you one, but we have to charge for the part. We always quote you the price first and never charge anything without your agreement.
The full rules are in "Do your kits have a warranty?".