Product Given to the Wrong Customer

I sent a courier company to collect products from another company within the same building as Evox. The courier ended up collected over R3000 worth of products from EVOX, products which are not mine and have been paid for by their customer. After allowing these products to be delivered to the wrong company they have still not come to collect their product at our offices and now we're sitting with a courier bill that we shouldn't have to pay. How can they allow this to happen. After attempting to contact head office through the Edenvale branch I am still waiting on a response... Every time I phone I get told \head office has not responded". I refuse to pay a courier for their fault. Worst of all is that their customer is still waiting on their delivery which is sitting at our offices... not even in the same country! """