NO COMMUNICATION!!!!

I was advised by an online merchant that they were unable to do my refund as there was a problem with my account, they then referred me to my bank (Tymebank) for them to do a charge back, they provided me with a letter and everything, I called Tyme bank and was advised to send an email to card services and they will call me back, I sent the email, it 3-4 days later and I still haven't received a call back from them regarding my charge back????