It's a custom order and it includes not only the stripes and lettering on the outside, but also the choice of fabric inside. There's no way they're re-doing a pre-existing bag.
Hrm. Although I suppose you could take the bag into your nearest store for a return AND THEN order a mon mono.
One more thought: don't order a mon mono online. Order it in the store because your monitor might now show the colours properly and you'll have little recourse if you're not satisfied with the colour once it's on or in the bag.