ITEM STILL NOT COLLECTED AFTER NUMEROUS PHONE CALLS

I have been so frustrated over the past few weeks, I have had numerous agents phoning me promising me that they would resolve my query and it is still not done. I am trying to return an item that cannot fit on a bike, yet the courier keeps sending a bike out. They eventually updated both queries to concluded yet I still have the item and now they say it is not eligible for return WHAT THE HECK IS WRONG WITH THESE PEOPLE. WHY DON'T YOU HAVE A CENTRAL CUSTOMER SERVICE TO ASSIST CUSTOMERS!!!!!