Terrible service in regards to my order

I placed an online order that was approved 3 weeks ago. They took the first debit order and informed me that they were out of stock. So on Friday the 12th of October 2018 i called the call center and they said that they received stock and they were booking the stock out to the courier that day and i can expect my delivery by Monday or Tuesday. This morning (Wednesday) i called yet again as i have not received my device just to learn that they cancelled my order and placed a new order and now they are out of stock yet again. So basically i have paid for a service that i dont receive and no one can give me any indication of when i will receive my device. This situation is unprofessional seeing as i did not even get informed that they made changes to my order and when i call they simply say i dont know.