Hi and welcome to the site, I’m Louie. Sorry you had to wait awhile but I’ll do my best to help.
Initially, does the base unit show that it is turned on? ...icators/display as expected?
Will the base unit work in SPEAKERPHONE mode? ...using the cradle/corded handset?
And for test purposes, can you please unplug the base unit and remove the batteries of all the handsets for an extended period of time?
Apologies for the delay, sluggish Internet if at all.
Still, I understand. Good luck.