I am not a lawyer and this is not legal or financial advice. Many service providers will allow pre-paying a credit to the account but if you want any kind of p

I am not a lawyer and this is not legal or financial advice. Many service providers will allow pre-paying a credit to the account but if you want any kind of promise then I think you would need to reach out to them, set up a business account of sorts and get a contract that agrees to your terms in writing reviewed and signed by lawyers. The account should be set up in the name of a trust or business. Pre-paying may be important if you suspect funds may be seized. Even then that does not stop the business from going bankrupt which in most countries would nullify that contract unless the bankruptcy judge determines that some law requires the acquiring company to honor your contract which is unlikely and assuming the email provider is acquired and not liquidated. You could probably also pay a money management company to pay your bills from a legal trust which vary by state and country and have all your bills route to them. I am basing most of this off the myriad of chapter-11's, mergers and acquisitions I went through during and after the .com bust which led to some fun arguments with vendors. Be sure to set up limited power of attorney with your lawyers so they can manage your email account. Set up forwarding to route emails to them as you won't have access to a computer or phone. If a prison had a shared terminal then the warden and staff would have access to your emails. Probably best to keep that between you and your lawyers. And/or set up email rules to forward emails with specific subjects to your lawyers. It would also be important to discuss all of this with the lawyers that would be involved in discussions with the sentencing judge so that for example the lawyers may be able to visit you with a laptop that has offline copies of emails as cell service may be blocked. Expect this to ultimately be paper hard copies. As for specific companies it is probably best to research the founders, board members, financials and company history of several providers. It's hard to predict which tech companies will still be around in twenty years. Even golden children like Amazon could be replaced by a new golden child but that is a much bigger topic.