Diagnosis, procedures, what are they doing?
More than that, what was the problem? What exactly was the seat doing? You said they tried to "put it back together", I know what those words mean, but in the context of a car seat they actually make no sense at all. Did the back fall off? Was it making noises? What happened, because fact is, there is VERY little anyone can do to "put a car seat together" it is preassembled in such a way that replacement is far, far, far, FARFARFARFARFAR cheaper than repair, so again these words make no sense to me. There is nothing to put back together, it is either in one piece or not. Probably I am misunderstanding your description.
This sounds bad but what you have written gives absolutely no information besides you are unhappy and there is some problem with the driver's seat. Was the back not holding firm, was it sliding back and forth on it's tracks, was it not moving at all, what was happening? Be specific.
What exactly did the dealer say, because MRI's are not performed on car seats. Magnetic Resonance Imaging doesn't work on metal and car seats aren't made up of bone, muscle or any other organic material. I honestly do not believe this, not saying you are lying, probably it is the dealer. Regardless someone isn't being truthful here. If the dealer actually told you this IMO they were making up a story. That is like telling you they are cooking a cast iron casserole in the microwave...it isn't going to work.
Are they trying to figure out why the internal structure of the seat broke? They wouldn't go to a laboratory and perform a medical testing procedure, they would take the cover off the seat and look at the inside. To suggest they would perform a test that costs thousands of dollars instead of paying a tech a couple hundred seems a bit unrealistic. If I were told that by a dealer, the first thing I would do is go and ask for a copy of it in writing. The second would be to see the vehicle disassembled, that is right, you can ask them to have a tech walk you back to the bay so you can see your car. Were I, you, I would ask to see my car immediately, cause the "stuff" is getting deep. I would literally tell the service writer to his face I believe he is a liar and I want to see my car immediately or I will be filling a police report against the dealer for stealing it....why? Because the second he told me they were doing an MRI on a car seat I would know he was feeding me a line of bullshit. Maybe I'm wrong, it happens, show the paperwork please.
If you don't have paperwork, but want to go to small claims court later...you better go get some paperwork if you want to win.
You say fixing the seat costs $1000, (which sounds realistic) an MRI test is double that, easy. Not to mention metal in MRI's period does not work. Period.
Does not make sense at all. 30+ years in auto repair...never heard of using an MRI. Sent a message to my sister who handles warranty paperwork for a Mercedes Benz dealer, she has also never heard of that. Several friends who run service depts. at dealers from Honda to Audi, same thing. Possibly you were just given the wrong name or are misremembering, regardless if you want help we need correct information.
You say you were told to call Alfa Care yet give no details on what happened when you called. Did you call? What exactly did they say? Did you tell them the dealer told you an MRI was being performed?
I assume you are telling the truth, just don't have all the information and the dealer is not being transparent - or truthful - however this is a very unbelievable situation. You honestly believe the manufacturer would pay the labor it takes to remove the car seat, then pay $2000+ to MRI a seat that costs less than $1000 in parts to replace? No, that is the definition of unbelievable, unless they are trying to charge you for diagnosis? The manufacturer would never authorize that type of expense to disprove a warranty claim, and the dealer would not pay that out of pocket either.
You should be calling Alfa and getting your paperwork in order.
This is not correct.