gonna throw this one out there, it's how I'd approach it if it were me... maybe it's useful?
Hopefully the email you got has a reply address? If so, that's your in - if it were me I'd drop them an email, ask if they'd mind explaining in detail exactly what prep they need you to do (providing access/clearing space for X).
Regarding the cable routing, whoever came out must have drawn up some kind of a plan (maybe back of a napkin? π). You could ask for a copy.
Most importantly though - be honest, explain what you're anxious about.. Express that you'd rather they communicate in writing (via email for example).
On an adjacent note, communication being in writing is also beneficial in the event that there is any mixup/mistakes - as there's a clear contemporaneous document that lays out exactly what you asked for, were told, when, by who, etc!
Also - how you feel about pressure, the phone, being put on the spot re decisions face to face etc. These are all customer needs.
If you spell them out, its not the kind of thing they can just say no to! π
ahh that's perhaps not as bad as I feared it may have been...
I've honestly hated having to say I need communication like this, and sadly I've had to be extremely forceful in some circumstances - just to get communication in a format that is accessible for me.
Sadly it's had consequences too - for example, one credit card company offered an interest free repayment plan... Really cool huh? Well... Only if you phoned them... I couldn't email and ask for it, I couldn't even do snail mail....
So I complained to them, got nowhere, had to go to the Ombudsman not one, or twice, three times!!
All occasions they ruled in my favour... I got a small amount of compensation, but still not the same thing they offered people without a disability.
The end result was they terminated my account. Presumably because people like me are not worth the effort... π
I think my aspie brain struggles with injustice, especially when I've experienced it myself, so always encourage people to stand up for their rights!
Anyhow, apologies if I was projecting a bit!