B737-700
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 100; Flight Crew Type 11000
Communication Breakdown
ATC Issue All Types; Conflict Airborne Conflict; Deviation - Altitude Undershoot; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Provided Assistance; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Returned To Clearance
Human Factors
Between ZZZZZ and ZZZZZ1 on the arrival at approximately FL 200; we were vectored off the arrival to the left/north and given a descent to 17;000 ft. We were told this was for traffic. The frequency was very busy. After several other calls; we were given; 'Descent to 10;000 ft.; no delay through 14;000 ft.' The Controller the made multiple calls to another aircraft. One of the calls was partially blocked with the end being 'direct ZZZZZ1' and another aircraft responding to the call. As we continued our rapid descent between 16;000 ft. and 15;000 ft.; TCAS gave a TA (Traffic Advisory) for a converging aircraft below us. We immediately switched from LVL CHG to VERT SPD and slowed our descent to 500 fpm. Shortly thereafter ATC queried as to why we had slowed the descent and if we were direct ZZZZZ1. We responded with the traffic alert and 'negative.' He issued direct and we responded. Once clear we continued the descent 10;000 ft. At no point prior to that did we respond to a clearance to ZZZZZ1. TCAS did not issue an RA (Resolution Advisory) during the advisory process.[Some] preventative measures [could be] keeping us on profile; making at least one aircraft predictable. Multiple vectors; multiple COMMS; multiple aircraft in dynamic flight; and one partially blocked call made for a difficult situation.
[Report narrative contained no additional information].
B737 flight crew reported an uneventful resolution to an airborne conflict due to a communications breakdown between flight crew and ATC during approach.