BSNL
Mobile portability request rejected by BSNL

I am a BSNL-prepaid customer from past 5 year, my no. is 9442811241.

recently for changing my provider from BSNL to other service provider i applied for porting and my porting has been rejected from BSNL Side

i got a message from 1901 that "There are subsisting contractual obligation from the Subscriber agreement"

and when contacted to customer care, they asked me to approach BSNL local office,

but in BSNL office Vaniyambadi and telephonic conversation with BSNL Thirupattur office i did not get any proper response.

i really don't know what is the reason?

Can you please instruct me how to resolve this conflict.