Worst travel agency ever!!!

We booked our boat cruise 18months for January 2018 in advance for a specific cruise. We received a quote (all inclusive) and paid in full by October 2017. Now that we asked for our tickets there is another amount outstanding! They pass the buck, give 4 different excuses, don't come back to us (although he is there and we can hear him talking), blame shifting etc etc. We are 32 people in our group going and EVERYONE is unhappy!!