@ Symbol as Insult?

[typod]

I've done a comprehensive google search about the @ sign being used as an insult or perhaps any alternative meaning.

Yesterday I sent a message to an eBay member about an item (As I usually do). I kindly asked them if the item had stickers etc or was from a smoke-free home. I thanked them in advance etc...

The seller responded about 20 mins later and the body of the message just says @.

Am I missing something???

I responded by saying "Hey, I'm quite interested in your item, is this an insult an oversight?"

NO RESPONSE

Seriously, just kind of confused and intrigued about the implications of this little symbol.