Transfer of articleship for industrial training

Pls Help...

I am in the 2nd yr of articleship and just 3 months are left from complement of 2 years of articleship.
After 2 yrs i wants to join industrial training as recommended by ICAI. So, i have already given a notice as per rule to my principal but my principal said that he wont sign form 109 and will not allow me to take transfer bcoz they dont have enough staff to complete work.
pls suggest what can i do in this situation.