You are probably going to have to call and or ask that business to turn off their call forwarding.
To Use Call Forwarding:
Pick up the receiver and press *72 (or dial 1172 on a rotary phone).
Again, listen for the dial tone.
Dial the number where you wish your calls to be forwarded, followed by the # key. (Speed Calling codes may be used if you have this feature.)
If the call is answered at the forwarded number, Call Forwarding is turned on.
If the call is not answered or the line is busy, hang up. Within 2 minutes repeat the process.
Once you have turned on Call Forwarding, the phone will ring one short time each time a call is forwarded. You can still make outgoing calls from this phone without interfering with incoming calls.
To Turn Off Call Forwarding:
Press *73 (or dial 1173 on a rotary phone) and wait for the confirmation tone.
To Use Remote Call Forwarding:
Lift the receiver and listen for the dial tone.
Dial the Access Directory Number (if you don’t remember is, call the business office) and wait for a special dial tone.
Enter the phone number associated with your subscription followed by the # key. This is the number from which you will be forwarding calls.
Enter your personal identification number (PIN).
Enter the feature code.