Appalling Customer Service!

Some time ago an order was placed via Blackleaf's website for two pairs of trainers. The order arrived swiftly which was great but on inspecting the trainers all was not good.
One pair of trainers had faulty laces. It was clearly a fault but a call was made to the manufacturer themselves to get clarification. They advised to return them as faulty as they were not as manufactured.
Before returning the trainers, we contacted Blackleaf customer service to check how was best to return them as we wanted to return both pairs for separate reasons. They explicitly said to send both together via a recorded means, preferably Royal Mail. We were also informed that a full refund of postage would be received on receipt of the returns. The items were posted back, at a cost of £12.98!!
After some time, the refund for the trainers arrived but nothing for the postage. Several emails to customer services later and there was still no refund or even a response from them.
Almost a month after purchase we finally got an email. It simply stated that the company did not offer a free returns service!
Many more emails went back and forth before Blackleaf finally admitted fault and offered a refund of half the postage. Half! I couldn't believe it!
How can a company say 'yes, return the items and you will receive a full refund of postage costs' suddenly turn around and say 'here's half, accept it and shut up.'
THE CUSTOMER SERVICE RECEIVED FROM THIS COMPANY IS SHOCKING AND IMMORAL.