Istore Menlyn terrible service

Bought a phone from Istore Kollonade. Very bad customer service. Returned it to Istore Menlyn. Manager was initially very friendly gave me whatsapp number to contact him. I followed up regularly regarding my refund. It has now been 18 working days since I've returned my phone. Still no refund. Manager is ignoring my calls and any enquiries. Whatsapl line is no help. Even calling them is not helping. I'm at a loss for words that this is the level of service from an Istore.