How can I get back contacts that I deleted?

Yesterday I setup my mom's account for icloud so she could have the find my iphone app on her and my brother's account. They both share the same account, so when I set it up all of my mom's contacts went onto my brothers phone. After I deleted her contacts off of his phone, all of her contacts were gone on her phone. Now I'm trying to figure out how to get her contacts back because when I went onto icloud.com the contacts were also gone. I backed up her phone yesterday on icloud when she had her original contacts, but I'm afraid to erase all the content and settings on her phone and rely on the backup. Does the backup for icloud work? Or is there another way to find the contacts without erasing her content on her phone! PLEASE REPLY ASAP! Thanks