Byju's — Not taking return or refund request

We have paid Rs 67000 to byjus . When we requested for return and refund they dint even reverted to us . They said we can return the product within 15 days of delivery time . But their was no response from them after teh delivery was done . We requested for refund immediately but their was no revert from them .pls help us to take our refund back from them