Worst online shop ever

I received the worst service ever from yellow sub trading online store. I thought it will convenient and pain free as theire stores are so packed. I'm staying in Kempton Park but I waited 6 days for my order on top of that they never responded to my emails. When I eventually received my order it was incorrect then I requested an exchange which was supposed to be collected Monday the 9th but up to tonight the courier hasn't come, it's so annoying when nothing is communicated to you and when you send emails they are never answered. My 1st time experience with yellow sub trading has been my worst mistake with online shopping thus far.