Byju's — Product refund issue

Address: 1st Floor, D‑1,Sector ‑3, Noida 201301

We have purchased BYJU's learning station program by paying some advance amount. at the time of purchase they told us that you will get full refund if you request for cancellation with in 14days of purchase. Now, after 5 days only I have started cancellation process through their customer care but the only answer is that their senior will call in 24 hours or the mentor will call. its been more than a week time and I have called them more than 10 times but there is no response from them and they are just wasting time. my request is to resolve this and get me full refund.