Please help, Blackberry 9720 unlock error

This phone was brought to me with only 1 mep code option remaining.
Although I looked through the supported list no 9720 is there so I calculated the code using 9700 but not enter the generated codes to be sure I read the code by imei and mep same codes was given. I also used 9790 to read code same was the codes generated now entered it but the phone is now blocked only direct unlocking can resolve it. I am using infinity activation for this great box.
Question is which model can I use to do the direct unlocking because it is showing error on all tested model numbers.
Please help with your knowledge.
Thanks in anticipation.