Prodution batch code on cosmetics

[device_input]

Hello

Need some help about batch codes.

I sold a Valmont cream on ebay. The buyer told me she used a batch code app to check the production date and she found on her app it was produced in 2012 and that the shelf life expired in 2015 (the screen shot of her smart phone she sent me was in an asian language I could not understand). She wanted a refund asap.

I highlight the fact that the app is not related to the official brand Valmont or any brand, just a consumer app I suppose.

The thing is I purchased the item on a swiss official website in january 2018 and there is no expiry date (i.e. EXP: 2015).

So can we trust those apps?

Being scared of getting a negativ feedback, and the buyer being aggressive,  I refunded the money asap.

Are these apps and these informations valid to request a refund?

Attached a picture of the screen shot with the info she sent me.

Thank you for your help,

device_input

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