Builder did not share authority letter and sending letters

Hello everyone, We, flat owners, are in dispute with a builder due to negligence in maintenance and not providing amenities as part of agreement. He has taken money for parking and did not return money of few flat owners so majority flat owners stopped paying maintenance, we sent a letter to builder regarding this but we got a letter from builder's employee stating our agreement is terminated with just a sign present and no name present besides 'for builder'. The builder cannot terminate agreement unilaterally however I wanted to know if builder's men can correspond with us without sharing the authority letter especially when it's about terminating agreement etc? There are 3-4 people signing on the letter and none of the signatures are of the builder. We are approaching the consumer court so wanted to know if this is something which we can bring up?