I've just found the fastest way to get Tyme to resolve any issue, or to at least contact you.
Email then, wait a few days, and you probably won't get any response. Then contact the banking ombudsman, and state that you could not escalate the matter as Tyme has not published any way of escalating any issues, and they generally do not reply to emails.
I got an email a few days later, stating that they have been trying to contact me for a few days
(unheard of during any of my past queries/complaints)
I however hope that this is how their customer service is going to be from now, not only if the ombudsman contacts them.