Not the bag I ordered

I bought a bag from Zando Global on the 3rd of June 2019 and only received it on the 2nd of July 2019. However the bag I received was not the bag I ordered online so I sent Zando an email (to service@zando) immediately and followed up 2 days later with no response. I then sent an email to customer complaints on the 4th of July but I also haven't received a response yet. I have been trying to call them since last week but they don't pick up calls, apparently due to high volume of calls. On the app it says that my parcel has been dispatched and not received so I am unable to fill in a return form. I want to return the bag and get my money back. I don't know what to do to get these people to come and get the bag.