signed into mom's phone with sis' account. contacts synced. mom asked me to add her contacts to phone. deleted no.s from mom's phone. got deleted from sis' phone. backed up on cloud earlier. how to get contacts back ?? URGENT !!!!!!!

Hi Everyone should have there own APPLE ID and NOT SHARE that is Whats causing problems All the contents of an iPhone / IPad are linked to The Apple id that why it should be only by one person. Cheers Brian

Without a clearer idea of where these contacts are stored I would recommend you contact Apple Care for assistance. They may be able to help you sort this mess out.

While it's not 100% clear to me what you actually did, I suspect they are gone. Contacts are not backed up to iCloud. They are synchronized across devices in near real time via an iCloud account. When you deleted them in the phone, that deletion was sync'd to the copy in iCloud and in turn to any devices also using that same iCloud account.

IF you have a backup file in iTunes on your computer to restore from, then yes, contacts are part of an iTunes backup. But they are not part of an iCloud backup as they reside separately in iCloud via the synchronization feature where iCloud keeps all the contacts linked to an iCloud account the same on all devices logged in to that iCloud account.

If you sign out of your sisters iCloud account and back in with your mom' account, her contacts should sync back to her phone. But your sisters contacts have likely been blown away (if I undserstand your post) when you deleted them.