Simple Phones publishes something almost nobody else in this category does: the complete list of countries it can provide a number in, which includes the United Kingdom and Australia, and it supports British and Australian English accents explicitly. Booking, message taking and answering questions are on every plan; the tier buys AI agents, languages and numbers rather than features.
There is no overage. Its own FAQ states that exceeding the call count for your tier releases your phone numbers, which is a hard cutoff and a service interruption rather than a charge, so the plan you pick has to cover your busiest month rather than your average one.