No pick up for my Exchange/Return

I am so disappointed with the service I received from Superbalist, Im having issues with regards to having an item exchanged/returnsed,I bought sneakers on the 13 November 2017 the sneakers were delivered however they are big so I logged a request to exchange to a smaller size. It's now 3 weeks later that my return hasn't been collected or processed after numerous attempts of calls I made to their call center. What a pathetic service received.