Email is notoriously spotty for communication. Even IF they saw your message, we’re all so inundated with emails and text messages these days - that we have a tendecy to ignore or "forget" about a certain percentage of them, even when we don’t really "mean" to.
Retry, call, and try other methods of communication. Try through people who might regularly interface with them, like dealers or other customers. Lots of small companies (especially European) also take frequent long vacations. Your message thread can easily get lost in the mix.
When you do resume communication, it might be wise to bite the bullet and purchase a couple spares, too!