ok first of all this is the first time i heard something like this happening in the las 3 yrs i been selling this product,people usually complains about their eyes getting irritated the first 2-3 days which is normal because is something new for their eyes so they have to get used to it, but thats about it, i never heard such a thing like that , i mean even if she is allergic to this product the reaction she should get is a really bad irritation nothing like her lashes falling off he said he bough it months ago? and she just start using a couple days ago? this is weird, people use something they bought right away especially something expensive like this to find out if the product really works, what if they left it for months in the car or somewhere else in a hot weather? this product needs to be in a good temperature,you have to explain him all this and you cant give him a refund because its been months since he bought it, ofcourse if you want to issue the refund go ahead its up to you but i suggest that you ask for the item to be return to you and once that you received make a refund, why? there is a lot of scammers out there maybe they just want this product for free after using it for months or maybe they lost the product, and they came up with this story so they can get their money back, when you receive the product check it out, you should be able to see if its been used and almost emptied or if is still full, you have to throw the product away of course this procedure is just to make sure they don't keep your money and product, as a me i cant issue a refund to you , i hope you understand,its been months and the story he provided you sounds fishy since no one else had this problem before but not only that ,the time lapse he said he waited before starting to use it dosent make sence, i hope i helped you and answered your questions. Thank you!