As you can see , the Priority is medium and it will take more take to get confirmations because you paid fees lower then the one recommended , next time you should pay what is necessary
I am in fact receiving this payment but the buyer has send the transaction with low fee. I had an experience in the past that the fund has been sent back, what do you think about this time?
Hmm , If I were you I'd take caution because this could be an attempt to scam .
And yes you are right , Bitcoins could go back to the owner after few days if it dosen't get any confirmations at all . I'd recommend you to wait more time and see if it get confirmations or not but I'am not sure if it's the case for Medium priority or not . Read more about BTC fees here : http://bitcoinfees.com/
EDIT : just saw that you got one confirmation .