We stopped personalising products on ebay begining of this year, too much hassle for the price points. What we used to do with customers who didnt leave personallisation was message them asking for info, if we didnt recieive the info within 24 hours we sent out a large letter (proof of delivery) to the customer with a letter asking them to contact us through ebay etc. Saved on destroying your despatch metrics and the customer was impressed we had gone to so much trouble. Worked for us..