BAD insurance co

Am buying new second-hand car.
Was due to pick it up tomorrow.
Got insurance co to switch insurance tomorrow 12:30.
They did.
Car will not now be ready for pickup 'til Tuesday.
Asked insurance co to extend cover on current car so I can drive.
"No, you can't be insured for two different cars."
Asked insurance co to issue temporary insurance for current car, and never mind the cost (which garage said they'd pick up).
"No, you can't get temporary insurance on a car you own."
Asked insurance co to amend insurance so that insurance on new car started Tuesday not tomorrow.
"We won't be able to get the paperwork to you on time because of the postal strike so you won't be insured."
Asked insurance co to kindly eff off and die. (But I had already put down the phone.)

Garage, after initial disbelief of this INCREDIBLE INANITY, may be able to sort me out with a courtesy car. Maybe. I will find out some time tomorrow morning. When I will have driven to werk, but may not be legal to drive home.

Grrrr.