I've been 3 weeks late (also for medical reasons) for a Hetzner payment more than once, and my servers are still running. They sent several emails, one was a reminder to pay and another was a warning about what date they would shut down service. So I guess their notice system isn't as straighforward as one week for everyone. Perhaps it's because I pay their invoices by bank transfer manually intead of by credit card. Perhaps it's because I pay more than €400/mo. I fact you have made me wary of changing to a credit card now, because those do fail from time to time!