Parcel not delivered

I ordered something online at the beginning of the month and I still haven't received my parcel. I called the call centre and was first told it is at the store and I must just wait for the email confirming pick up. The email never arrived. I called again after days and was advised that the parcel is still with the courier. I'm not sure what is happening but I've received no communication even though we are over the promised SLA.