BAD SERVICE! NO RESPONSE FROM CALL CENTRE!

I have been a Courier Guy client for almost a year now, without much hassle. But I sent a parcel on the 15th and it still hasn't arrived. The receiving party has not received the parcel and the call centre has not helped one bit, the phone gets transferred and it cuts, and no one calls back. The damage this is causing my business is bad. I'm furious!