I meant to post this sooner, but forgot, but please be aware, if you call these useless fools, you get charged an extortionate amount for calling their 0845 number, and they aren't averse to sticking you on hold for long periods either.
I learned this recently, when having changed the day of a delivery the item didn't come, so I called up to find out what was happening and it turned out they had cocked up, I then spent the best part of the next hour and a half being passed from one moron to the next and repeatedly being put on hold, at no point was it suggested that they could call me back.
To my delight when my phone bill arrived, I had been charged over £40 for these calls!!
To be fair to DPD, when confronted with a scanned copy of my phone bill and a fairly strongly worded email they refunded me the full amount, and actually rounded it up to £45, so, a heads up, if you find yourself in this situation, push for a full refund, and communicate in email with them, its free!!! (ironically, when complaining about the cost of the calls over email I was advised I needed to CALL their complaints line, which surprise surprise is another 0845 premium number....I declined and kept everything in writing over email).