I get notice from service provider

Hi Sir, i am Sanjay Garg and i have taken service from iSpark , we have taken serivce from him and he give us invoice in every 3 month and they charge advance payment always. in covid - they send me email for payment and our time is 15 days extra and i ask him for discount but they deny then i told him we are not interested and not taken service. after that they regular folllow up and want 3 month payment for Rs.. 44,000/- but i told him i have not taken serivce from you and it is prepaid service , if i not paid then u need to stop but they are not checking this point and today i get legal notice from lawyer for the saame for recovery of Rs. 44,0000/- with 7% interest. i have all email communicaiton where i told him that this is prepaid serivce and we will not pay if i have not taken your serivces. kindly help me now in this. Thanks