Ford India — change engine oil

Address:

Allahabad, Uttar Pradesh, 211001

I have purchased an eco sport in october 2014 and last service of my car was done on 11th november 2017 (Meter reading 15302).in that service engine oil was also changed charging rs. 1056.29 by me.
Just after four months a display is showing in my car "engine oil change due service required". During this four months my car ran only 1200 kilometer.
Then why this notice is showing on my car i cannot understand.
I also asked the representative of ford that engine oil should be changed in my presence at the time of service. However, when i reached the service center engine oil was already changed in my absence.
Please intimate me what action should i done and what is the reason for the same.