near total hearing loss to receive and hear phone conversations?

What have people with near total hearing loss to receive and hear phone conversations?
My 84-year old grandmother is deaf in one ear and has near-total hearing loss in the other. She wears hearing-aids but can not understand alot of words.
What appliances can you suggest (bonus: where can I purchase them online) that can assist in [...]

What options are available for people with near total hearing loss to receive and hear phone conversations?

My 84-year old grandmother is deaf in one ear and has near-total hearing loss in the other. She wears hearing-aids but relies on lip-reading to assist w/ comprehension.
Phone calls can no longer be accepted because of her condition.
What appliances can you suggest (bonus: where can I purchase them online) that can assist in this [...]