You order and pay and they deliver to someone else

I made an on-line purchase with TWISP on 20 July at 12:40 of R500 for delivery to my company address as I always do for almost years now. The process is usually efficient in that SMS's are sent of delivery status. And delivery is made the next day. From the time of order until today the only correspondence I received was purchase confirmation (20 July). Today 22 July I call TWISP to find out where my order is as I did not receive it and did not get SMS's of status. according to their records they delivered it yesterday 21 July to someone I don't know. I have called TWISP 5 times today - 4 calls to DISPATCH (Nishaan) and 1 to management (rude lady JACKIE cut the call). I contacted my company mail room 6 times- the parcel is no where to be found. According to TWISP dispatch it is not their problem as they delivered the parcel and have confirmation of delivery to Lebo. I ORDERED the items, I PAID for the items, the items should have been DELIVERED to ME. I am absolutely disgusted at the unprofessional and unacceptable attitude and service received from TWISP. They should take responsibility for what has happened and rectify the situation - their processes have changed their problem!