OK, that's the model of the phone, not the model of the phone system.
Di this: Pick up Line 1 and call your cell phone. Answer your cell. This is just to get a "clear" line with no dial tone.
Press Feature and dial #1
You're going to hear the Touch Tone digit 1 dialed out. There might be a series of 1's and then a pause, and then some more 1's.
Post back with the the pattern of digits, (like 3, pause, 1), and we can tell you which phone system you have.
Then there is a possibility of restoring your programming, or getting it re-input from scratch