If "andrejka.123" really does represent Sawgrass (and we have no way of knowing), the email sounds like a very clumsy way of saying "you don't have a license to resell Sawgrass ink, so stop reselling it".
The only avenue open to you is to contact Sawgrass directly via their website (or a phone number listed on their website) and request clarity regarding users selling on their unused/obsolete/2nd-hand stock. They may well say that you can't sell it at all without a license, or they may let it go and keep an eye on future listings to be sure that this really is just a "one-off" - but, in either case, at least you'd hear it from the horse's mouth and not from some faceless ebayer.