x5 has rough idle and check engine light after an oil change at NTB

What is your question?

This car has been great with no problems until I took it to NTB to have oil changed, then 2 days later began getting rough idle and the check engine light came on and then began flashing. They forgot to put the oil dip stick back when changing the oil, and had to replace several gaskets and the oil sender unit (I think), now they want to replace the spark plugs and cables because of pin 4 misfire ( they told me that is what is causing rough idle, because evidently oil got into the spark plug and coil ). Not sure if they are just stabbing in the dark and guessing. I feel like the messed something up when they did they oil change, but don't know enough about it all to find out. Maybe I could repplace the spark plugs and coils myself, but not really sure if that is really the problem