You can probably claim they are not answering their phones, but what would that do in small claims court? Do they have some legal duty to answer phones at all,

You can probably claim they are not answering their phones, but what would that do in small claims court? Do they have some legal duty to answer phones at all, ever? Can't they just say - "oh, if we see that Lio is calling, we would never answer them as a matter of policy, and it's fully within our rights to do so!" ? They might be required to have a legal address and be reachable by certified mail, but IMHO there's nothing wrong with a business (no matter how large) simply having no phones at all.