I need help please 
I am sponsoring my mom & receive a letter from CIC instructing me to send the additional information to PO box 3000, but as per website instruction for other family class applications it should be PO box 6100? Kind of confuse which one to follow???

I am sponsoring my mom & receive a letter from CIC instructing me to send the additional information to PO box 3000, but as per website instruction for other family class applications it should be PO box 6100? Kind of confuse which one to follow???