Tata Motors — TATA Nano car

Address:

Pune, Maharashtra, 411043

Hi,
I'm frustrated customer of TATA NANO [Pune].
I'm getting check engine alarm on dashboard within 15000kms & this prompt comes erratically within 5-6kms in morning cool atmosphere.
I handover my car to TATA authorized service center & I came to that few parts [e.g. O2 Sensor, Spark plug, Spark plug wire, Ignition] needs to be replaced.
I was ok with the replacement but unfortunately parts were not available with TATA. I checked with other TATA entity also but nobody have those parts.
This is very surprising that authorized TATA Server Station don't have stock of the parts & I need to wait for 8-10 days [& why I have to pay in advance amount for parts which is getting after 8-10days] for the part replacement. So as per my understanding if parts are not working properly then it is risky to drive a car.
I would request to concern team / person to look into this which is really inconvenience to end customer...