Zando online store - lack of customer service

Zando's customer service leaves alot to be desired. I'm impressed with how quickly I received my order, it was placed the Friday and I received it the following Monday morning. However on inspection of my shoes I discovered a defect in the right heel and attempted to get hold of them by phoning their customer services to enquire on their return process as I'd bought the shoe with a discount coupon and wanted to know if the discount would still apply if I returned the defective item to be replaced aswelI as to what my options would be regarding the waybill that needed to accompany the item upon return which wouldn't have been possible as I don't have access to a printer. That same morning I phoned their customer services 10times between 8.15 and 11.30 but no answer. I then decided to email my complaint which is now entering it's 4th day and still no response. I decided to phone their customer services again yesterday(6.6.2018) and again a few times today (7.6.2018), unbelievably still no answer. What good is a customer services department when it cannot fulfill the job of servicing said customers? Zando needs to catch a wakeup as I'll think twice before any future purchases. I want them to contact me asap as I want these shoes replaced before it's completely sold out.