Complaint regarding suspension service not rectifying the original damping problem

I am filing a complaint regarding a motorcycle suspension service provided through a bike workshop. I gave my motorcycle suspension to the workshop because the suspension damping was not functioning properly. I clearly communicated the issue to them. The workshop removed the suspension from my motorcycle and sent it for suspension service/repair. The suspension was kept for approximately 3.5 months before I received it back. I paid ₹5,500 for the suspension service. I also paid ₹800 for an engine oil refill, making the total Google Pay payment ₹6,300 on 19 September 2026. The workshop did not provide me with a formal bill. However, I have WhatsApp conversations and voice notes relating to the suspension, as well as the Google Pay transaction proof showing the ₹6,300 payment. After receiving the suspension and installing it back on my motorcycle, I found that the same original problem remained — the suspension damping was still not functioning properly. I informed the workshop about this issue. They told me that the suspension had only a 3-month checking warranty and that they could not do anything because the warranty period had passed. I explained to them that my complaint is not about a new problem developing after the warranty period. The original damping problem for which I gave the suspension for service was still present after their service. I requested them to inspect the suspension and provide a solution, but they refused and stated that they could not do anything. I therefore request assistance in resolving this matter. I request that the workshop be asked to inspect and rectify the original suspension damping problem, or provide an appropriate refund/compensation if the service provided was defective or inadequate.