As you have asked about the Indian Forest Service (IFS) coaching centre in Delhi, I am mentioning them, check below for the details

Evolution  
Civil Services Entrance Coaching Center
Address:
B 11, 2nd Floor, Commercial Complex, Near Icici Bank Atm, Main Road, Dr Mukherjee Nagar, Dr Mukherjee Nagar, New Delhi, Delhi 110019
Phone:011 3297 4645

Destination IAS Academy Coaching Institue  
Civil Services Entrance Coaching Center
Address:
M-2, Jyoti Bhawan, New Police Lines, Mukherjee Nagar, New Delhi, Delhi 110009
Phone:099119 45480

Career Plus  
Coaching Center
Address:
C-106, Sector-23, Near Gail Vihar, Noida, Uttar Pradesh 201301
Phone:092104 88730

Vajiram & Ravi  
Coaching Center
Address:
9-B, Bada Bazaar Marg, Old Rajinder Nagar, New Delhi, Delhi 110060
Phone:011 2582 0000