Satelite phones are the most reliable and maybe even the cheapest way to stay in email contact.
SSB email requires a very carefully installed system with a very good rf ground or the noise locks you into endless cycles of sending the same packets over and over again. This eats the amps.
If you are having reception problems that you can detect with voice transmission you probably have a very marginal rf ground plane. Even when the voice communication sounds fine the ground may not be good enough for email.
SSB does require an expensive modem that can cost up to $1,000 and be a pain to install and learn to use. $1,000 can buy a lot of satelite phone time.
Using your cell phone in a foreign country can cost more than the satellite phone on a per minute basis.
Using a satelite phone is pretty much as easy as using a cell phone. In an emergency, that can be a major factor especially if the operator is not someone who is very knowledgable about
radios.