How can I connect a phone line to a sound system

We are trying to connect a telephone to a soundboard in a church so a missionary can call the church and the congregation talk back through a sound system mic. I had the sound man make the connections on the soundboard while I connected to a telephone extension on their telephone system by connecting one pair of wires to the mic in the phone and one pair to the 32 ohm speaker in the phone. When he connected my mic leads to the sound system we could hear though the sound system, but we had a hum. When he connected my speaker leads it blew out the speaker in the telephone.
Please share your ideas, or if you have done this before, give us some instructions.

Thanks,
Gulftech