Ryobi

We purchased a Ryobi electric ride on mower from Home depot for our residential home in Fla.
Less than 2 years after purchase it was not working correctly. We did some research and changed the batteries $800.00. Same problem after we changed them. We called Ryobi warranty dept. They sent a service Tech over to tell us our warranty was voided because we did not use Ryobi batteries.
Nowhere in the service manual or on the mower does it say that the warranty will be voided if you choose to use different batteries. I am so disappointed and disgusted with them. I lost all respect for this company for not standing behind there product.