John Lewis on-line shop steel customer's money

My wife buys from John Lewis shops quite often. Recently after visiting the shop she realised that pillow cases were not include with the duvet she bought, so she went on John Lewis web site and decided to buy on-line 2 pillow cases that match the duvet.
What really arrived was one single pillow case instead of two she paid for and not the one she ordered.
She contacted John Lewis customer service by e-mail, but was told that she had to call them.
During the call it was agreed that they would send the correct goods and refund the price of delivery.
She waited for a week, but while the delivery cost was refunded, the goods were not delivered.
She sent another e-mail asking why and got a response that they run out of this type of pillow cases asking her to call them again. As if she has nothing else to do but to talk to their customer services.

Effectively they have stolen our money as it seems we have already had enough interactions with them to make all this business of talking to them completely useless.