Backup Batteries

Purchased 2 Natlon 200 AH batteries on 28 February 2020, they along with an inverter were installed the next week. These batteries should last about 5 years, 2 months out of the warranty the batteries no longer hold a charge 'according to Natlon who tested them'. Tough luck consumer , whew our batteries just made the warranty. No explanation , no attempt to discount replacement. There are much cheaper batteries out there which will also only last 2 years and 2 month so rather go for them.