No serivce under replacment

I was dealing with a Reputed pump company from coimbatore. i was making with them both the purchase and payment as per specified terms till 30th of december 2017. i have sent them replacement pumps for 1.42lakh on 5th september 2017 and have not received my replacement till 30th december and hence forth i had to pay them 2.66lakh(before replacment). After repeated intimation for service they did not reply. at the 30th march they said you have outstanding hence we have not done any replacement.I lost hope from the company and hence i said them not to send the pumps and adjust the amount for the same into my account. Furthur by may they sent 20% worth material pumps but non saleable condition and i intimated them this could not be sold. Again is sent material of Rs.22000 by 30th june for service. They said they would service and send but still they did not send and hence i have to provide new pieces to customer. Now i hold replacement pieces upto Rs.40000 in my permises. And still 2.5lakh worth material lying idealy my godown and each product carries 2years warrenty. Now they have served with notice on [deleted] with acknowledgement stating outstanding and request for payment . I am struct with it what to do. please help me with this for same