POOR COMMUNICATION AND NO CUSTOMER SERVICE

I received the shoes I purchased with no hassle, but returned it back to them to get a bigger size. They have had it for a week now and no communication has been given to me. I they ignore ALL the whatsapp messages I send, a blue tick is all I see. I paid so much money to them for shoes and they DON'T EVEN HAVE THE AUDACITY TO COMMUNICATE BACK TO ME.