Cabled landline replaced with a cordless reliant on electricity

My friend had her landline replaced with a cordless phone, that relies on electricity to work. She did not ask for it and with al the power out situations, her phone cannot charge and she is without phone for days on end. She is 85 and lives on her own. She needs her phone for when she is in need of help of whatever kind. Telkom refuses to reinstall her old cabled phone. Please help. There must be a solution to ensure she is connected at all times.