Mango Order Error, Missing Refund

Recently, I had a problem with my Mango order. Two items were canceled because they were out of stock, and I had to send back the other two. But I only got a refund for one of the things I had to cancel and not the other. Even worse, the customer service rep said the money for the missing item had been refunded, but I couldn't see the money in my online account. I even went to the site and saw that three of the four things I bought were still there. I feel cheated and like I've been hurt. I want Mango to give me my money back as soon as they can. I won't give up ever. I will put my complaint on all kinds of platforms for complaints.