Complaint -Courier It

At this point I am ready to have a meltdown....my parcel was said to arrive on the 13th of December as per sms I waited and nothing happened,the evening I checked and it showed delivered and that's where the trouble started,I have been back and forthuntil now with these people who are unapologetic,*********** and downright suck at customer service,spoke to about 5 people of whom none can answer me they keep saying it is being investigated and has since been escalated well it's been two days since anyone has made contact with me for follow ups,I have spent airtime money and wasted my time explaining everything everytime to someone new because nothing has come of it,I am very patient and have been more than fair but now they are pushing my buttons I guess they will simply close business for the holidays with not a care in the world and life goes on while I wait to be reimbursed even the driver who once was nice is now just ignoring me but reads my messages,what am I to do? Who else can help because all they do is point fingers and there is no accountability I am FED UP WITH THESE PEOPLE SO COURIER IT YOU SUCK BIG TIME!