2 models, Old style 3 Band cell phone issues w/AT&T

Has anyone else been having issues with various older style phones with all these signal upgrades? While I'm complaining and looking for sympathizers I'd still like to know if there is something else I might do other than buy a new phone.

Gave Grandma an old Nokia 3120 and it worked great for her (no frills, easy use) but after a few years the volume kept dropping so she can barely hear on it anymore. Tried new battery, no change. Had 2nd Nokia 3120, that was packed away but now in use, that suddenly had the same volume issues too. Both used to have killer volume.

Also we had 2 Motorola RAZR V3's that worked great for years but the new replacement batteries suddenly don't last more than a few hours in either of them.

QUESTIONS:
Would signal strength cause speaker volume to drop?
Would new batteries (bought months apart) go dead from signal search?
Could AT&T be playing with 3 band signal strength to force users into costly upgrades? Perhaps not supporting old system users anymore? like Microsoft does.

I see AT&T has been blaming their problems on end users lately :4-thatsba that applies to internet usage too. Their attitude and customer service/satisfaction ratings are getting a bit ripe.

Coulda, woulda, shoulda.
I'd love to hear from you.
digit