All inclusive website no longer accessible after changing tariffs (server move) – what to do?

I've already written to all-inclusive support but am urgently looking for a quick solution; Maybe someone here can help more quickly.

Last night, I switched my hosting plan to "PrivatPLUS." Since then, my websites have been unavailable—it's been nine hours now.

A server change was necessary, which is why it said that the pages would be temporarily unavailable.
But now I need them again for my daily business.