Popular Maruti — Due to bad fitment of spoiler my car started resting

Address:

Shameer.M, Qtr.no:153 type ll,sector "A" ,GC CRPF Pallipuram, Andoorkonam p.o., Andoorkonam p.o.

I Mohammed shameer purchased maruti Suzuki ertiga KL22M 5973 from maruthi popular Trivandrum.
As accessories company fitted a spoiler on payment.
Due to bad fitment car body started rusting and I reportedly shown this matter on every service, and service centre told me it's no problem.Now the rusted spot changed to dark.
Please take favourable action as early as possible.