Counterfeits - some advice: Before bidding check the seller's record of feedback. Have any been refunded as counterfeits?
Then ask the seller if the balls are genuine and how he knows this - where did he get them from ?
If there is no close up photo of the ball and box to enlarge, ask for one. Enlarge it!
You should see no straight line of dimples around the join between the two halves, nor a gap between the dimples nor a join of any kind ( that's what it says on the box ) . The ball surface should be entirely covered with the correct size and shape dimples - compare it with a close up of a ball offered on Ebay by a PGA pro shop. If you detect any undimpled area or an apparent join line then it is not a Titleist Pro v1.
If you receive suspected counterfeits test one with a putter. If it makes a "ting" noise it is a cheap two piece, Titleists make a low " thud " when hit. Look at the black print - is it in any way faulty ? - Titleist do not sell balls with any print faults whatever - I mean none whatever otherwise they'd be x - outs. Is the ball-cover smooth to touch or rough when you rub your finger over it ? Titleist balls are glassy smooth to the touch. The paint is perfect and brighter white than the average. Are the boxes rough anywhere on the surface- Titleist do not make boxes that are less than glassy smooth all over. All this may be why they cost more?
Best advice is to compare what you've bought with a genuine box and ball from a Golf shop- you'll soon see the difference.
Oh and the counterfeit balls will likely be cheap £2.99 a doz. overruns that break and make circles in the air and go no distance except when they bounce right over the green so you're wasting your money - better to go and buy some £2.99 cheapies from the Sports outlets and save yourself a lot of money compared to the counterfeits.