Your running is not very high and you own a pocket friendly car too , so avoid AMC from next time. AMC'S are best taken for high end cars whose maintenance is a bit costlier.
For your running you should be servicing your car once in every 6 months according to your manual i guess.
Now few questions:
1.Do they change the brakepad each time you service your car? If yes then kill them , for your running brakepad will last for even 3 years!
2.Then if you changed your wipers only recently , within 6 months , then don't pay for the new one! Demand a new one free of cost because it is manufacturing defect!
3.What do they mean by total body and injection? AFAIK
underbody rust coating is done only once for a car which lasts for upto 5 years and for WagonR it must cost around Rs.2500 to 3000.