Usha — Water Heater not replaced or repaired by the company

Sir
I have purchased a Water Heater o[censored]sha Company Model - MISTY252 SN:- ME[protected] on 22/07/2020. Its not working properly right now. i have lodged a complaint to the company and the service executive told us it is still under the warranty. After following his guidelines we submitted the above water heater to agency for replace. But the agency refused to do so. Kindly help me regarding the matter. as a customer I am more than 75 years and unable to move from my house. kindly help me.
Agency Name
NUTAN SALES
Near MES Gate, Booty More, Ranchi-834009, Jharkhand
Mob No. [protected]