Byjus - BYJUS REFUND NOT DONE

I have optioned for grade ** & ** Byju’s tab and week end courses for my son. He went week end class few months and he feel that is not comfortable for his current study and He optioned for private tuition's for individual subject for computer science.
we have paid one-time lump-sum and optioned for ECS payment (Even though I am NRI and capable of paying single payment) Because of confident level of Byju’s coaching other than advertisement / Byju’s representative (earlier no reference from his school student or known sources).
I have informed through phone call to his coaching center as per Byju’s center advised to send email and I have mail to concern person to coaching center there is no responses, the same email forwarded to Byju’s cancellation and refund email id found from Byju’s web portal till the time there is no responses. Even though at least in every week I am getting * to * min. call from repeated answer they don’t know about cancellation and they are calling from finance department for payment due. My airtel number is roaming status (currently in United Arab Emirates) every time the call duration is at least ** to ** minutes. Every time of calls I was telling that this number is international roaming, but they are not bothering, and their interest is picking money from my pocket. Yesterday call was ultimate threatening saying that they are going to take legal action against me. How their behavior to parents and I feel very shame to chosen wrong institution for my child without proper inquiry about the institution and their agenda is only getting money from parents. Time god My child is lucky he quite from classes even loosing of paper (money only).