Extremely bad service from Adidas

I bought sneakers from Adidas online in December last year and logged a return because they don't fit. Up until today the sneakers have not been collected fron me which means I haven't gotten my return. I've sent numerous emails and calls, all I get is promises that the issue is being escalated. A courier company will contact me within 24 hour etc. But up until today im sitting qith tvheir sneakers. Avoid using their online service if you want peace of mind