Bad customer service dishonesty by not refunding

I have order boots online,once delivered the boots were to small and I arranged a return. Once returned I was advised that a gift card would be sent but bear in mind I purchased on the 29th June , started process of returning on the 15th July, item was received on their side on the 22nd July, no further contact was received during this time I liaised with Llana Vallabh the entire whom gave me all sort of excuses of system changes as I then proceeded to contact her again on the 1st Aug do a follow, she rep**** that the voucher would be sent thereafter. On the 8th August I again done a follow up to receive my voucher and again advised that a voucher will be sent at the end of day but to no avail. This is my money and I want it's worth,I will never support Contempo again due to this bad service not valuing customers and not honoring their word. This is the email received yesterday : Hi Andrea,

This will be sent to you by COB today

Nothing has been received thus far.