Mercer INFERIOR UPS battery replacements!!!

My UPS 3000VA batteries replaced November 2021 and just over 7 month later, they don't even last 2 hours when only running a router (12V & 2A).

I call their technical dept and I get told a UPS is meant for a laptop, to 'savely' turn it off, WTAH? What utter *******, I got them for the router, i.e. internet connection...

I easily got 4 hours out of this UPS before and loadshedding only started in earnest recently and now all of a sudden it's down to less than 2 hours.

This is not acceptable, last time it lasted at least more than a year.