Nippon Paint India — Painting Touchup, Invoice and Amazon coupons not received

I haven't received any invoice from Nippon Paints India and the representative (Sabarinathan) is not replying back to calls / messages. The service is so poor but they talk like they are the top in India. It's very frustrating that even after paying full money at once and giving them contract they don't do the jobs we need to micro manage each & every step.