Laptop accessories not returned

I purchased a laptop from FNB online. After a few days it was faulty, FNB asked a repair company to address my laptop. They could not repair the laptop and sent me a new one instead, but they did not return my accessories. After 4 months of emails they finally returned the laptop bag and mouse but not the USB modem. See their repsonse below:<br> \We checked in our repair centre unfortunately we could not locate the USB device.<br> As per the packaging instructions we provided