Q: I have a 2005 545i on my dashboard it had a key with a line through it at warned me if you turn off the car it may not start it

BMW dealership told me I needed a new ignition switch because there was a key symbol with a line through it on my 545i 2005 They then told me I needed a CAS unit for another $950 I called baloney they drop the price to 1350 total they then called me a week later asking if I have an extra key my answer was no another day and a half later they texted me back do you need a new fob key or a valet key to start the car but the car is communicating with them now I told them that's like buying a new car coming to pick it up and them saying all I didn't know you needed tires I asked them I believe it was the key the entire time that is the problem I have not answered me I'm looking for advice

My car has 100000 miles.
My car has a manual transmission.