The contract is invalid.
Step-by-step explanation:
- An online though it has some cons like "cannot touch and feel, color may slightly vary from the original to the picture given, quality cannot be measured, etc". 
- But the scenario given here is the expected / ordered color is different from the received one and it is wrong that the website is not accepting. 
- This website is not user-friendly and the fault from the website side is not accepted which once again re-insist the unfriendliness.
- Any website should allow the user to do easy exchange and returns because of various reason said in point no.1. 
- If the website continues with same invalid contract, then it will lose its name and lose the customer too.