Bharat Sanchar Nigam [BSNL] — Bill paid twice but the extra amount is not refunded back to my source account

I have paid my bsnl landline bill of rs. 1061 twice by mistake through "simpl" on 7th [12:23 pm] and 8th [02:32 pm] of september 2020. Both the payments were successful debiting the amount from my "simpl" account. Later i tried to claim the extra amount to be refunded back, but bsnl has refused to do so. The two transaction ids are as follows:

A] bbx[protected]qc
B] bbx[protected]wy

I have also dropped a mail to [protected]@bsnl.co.in.
I haven't received any reply from them.
I want the extra amount taken by bsnl to be credited back to my "simpl" account.