No refund received

I ordered a few bottles of Nescafe Espresso from Woolworths online. A few days later I was informed that they have fewer stock than what I requested. I told them to send me the stock they have and credit my account for the remainder. I received the product but no refund for the remaining bottles. Their online listed numbers are not working and they don't reply to online queries. Thus far Woolworths online services are the worst experience I've had. I'd rather stick to Pick n Pay, Checkers, Makro, Takealot, etc.