Gate intercom repair or renew?

Gate intercom repair or renew? Our videx gate intercom was paired with a binatone handset that we could open the gate from. we suspect rain got in and also the buzzer is broken. can't get it to work and have left it for years! Need advice on whether it's best to try and fix it or just renew. Don't know what is salvageable or what to replace it with.... Where to start. Trying to be efficient both time and expense wise. The buzzer radio signal has been detected by of com as it is interfering with a cell phone company signal in the area. Needs sorting fast.