Why do I have to give even one star

I bought from mangostreet only because I was getting a 50% off coupon. First they were not able to trace my payment. After 2 weeks they stated that the products are not in stock currently and I have to wait. I insisted on refund but they maintained that the order will be sent ASAP. I kept on insisting on a refund and they agreed. 3 months have passed and I still haven’t received any refund inspite of numerous mails… Now the website isn’t working, they have been inactive on their Facebook page too.