Toyota — Horn not working

Address:

500008

I bought innova 2.5v in 2010 from harsha tayota hyderabad hightech city rd. Since last one month horn is not working. I send my vehical to the same service center. Thet told that it is under airbag and it will cost rs 15k to repair and the parys are out of stock.
Later i came to know that it is a manufacturing / designing problem. Toyota called back so many vechcals to rectify the issue.
Why the same service is not applicable in my case.