I understand about times being tough, and won’t pretend that it’s no big deal.
However, you have a significant investment in your car, and servicing it is a form of insurance for that investment, in terms of both warranty and keeping it running in the longer term.
It will also make a significant difference to the resale value in the future.
So maybe consider how tight is too tight?
Possibly if money is too tight to pay for the dealer servicing, you are better bailing out of the car now?