Absolutely unreliable & customer service rubbish

I booked a DHL express Collection and delivery to Amsterdam with the premium delivery guarantee for pre 9AM. This was for a very important tender in Amsterdam and 11AM was the absolute deadline.
I was convinced that with the premium guarantee and the two hour delay between the delivery time and deadline I could rest assured that this would not fail. However DHL were able to mess this up and they delivered the package at 11:50.. Our disappointment after preparing for days for this tender is obvious but i decided to remain calm and call DHL to at least get the 50 GBP refunded. A friendly lady apologised for their failure and committed to refund me for the costs incurred. However, when i received the confirmation email i noted to my surprise the cheapo's at DHL had decided that i would only get the premium cost back which was 18 GBP. Utterly disgraceful and pointless. I told them to keep the 18 GBP and we will not be using their services again.