Paytm Mall - Package not delivered

I ordered a product on **th April which was an IN-ear Skullcandy supreme sound headphones ink'd *.* with mic. The product was supposed to be delivered on the **th of May but didn't get delivered. I called the Paytm care on ** of May and told them about my problem and asked them to cancel the product to which they agreed. Again I called on ** May for not receiving my refund to which they said they have filed an application and my refund will be provided within ** hours. Its **th of May I didn't receive my refund and called them again to which they said they didn't file any complaint on **nd May regarding the refund and they are continuously delaying it even after knowing the product wasn't delivered. I received a message saying the product was delivered during midnight **th May. Now they are asking me to wait again and I am tired of their misbehaviour. Kindly help.