Vespa — replaced faulty battery with another faulty one

Address:

Hyderabad, Andhra Pradesh, 500081

In sep18 the service center (Shrey vespa, jubilee hills, hyderabad) replaced the nin functioning battery with the brand new one by charging the cost of the battery. The new battery also stopped working within 5months from the purchase date. When i raised a complaint at the service center, they replaced the battery without charging anything from me as it was under warranty. Now the replaced battery also stopped functioning within 8 months of the replacement. When i raised the complaint the service center is asking me check with the battery supplier directly. I am not sure why i need to check with the supplier when i bought it from the service center. Also not sure why the service center is so reluctant in the complaint raised with them. Please help me in resolving this issue.

Regards,
Sukumar