> d) Appointments are only granted by means of contact that don't reply.
Similar thing happened to me recently with the IRS. Got a notice about them needing to verify my identity and gave me a number to call. Had been calling for months and would always get a message saying they were too busy and to try the following day. After trying a few other options to no avail, I decided to show up at my local IRS office without an appointment (which I couldn’t get anyway). They first turned me down, then told me that maybe if I waited for a few hours they might be able to see me at the end of the day, then after about 20min and them clearly not being busy, they talked to me and was able to resolve the issue within 15min.
So, even though I was told I couldn’t show up without an appointment, and they tried turning me down, just by being there they finally paid attention to me. Yes, it was uncomfortable and annoying to have to do that, but it worked.