Howdy E_Ack, I hear ya, the visual voice mail is a great feature. At this time, we aren't projecting for this feature to free, but that doesn't mean that it won't happen in the future.
Kind of sad that it's not free as it would be very accessible for those with hearing losses who cannot use voice mail like myself.
I'm wondering if we have an accessibility tool that might work for you @Julesag95
I'm going to reach out to someone. I'll post in here if I find anything out.