EMB ERJ 135 ER/LR
Flight Crew Air Transport Pilot (ATP)
Situational Awareness
ATC Issue All Types; Inflight Event / Encounter Fuel Issue
Air Traffic Control Issued Advisory / Alert; Flight Crew Diverted
Airspace Structure; Company Policy; Procedure; Weather
While inbound on the arrival we were issued numerous and unusually extensive vectors for spacing by ATC. The frequency was very congested. When asked how much time off course to expect; the answer was an indefinite amount of time; we did not have an indefinite amount of fuel. More specifically; when I asked ATC how much longer; the answer back was 'as long as it takes'. Followed by 'this is all your companies fault'. We texted this information to dispatch and they were aware of the situation. After extensive turns to the South; East; North and then back Southwest; we decided to divert. ZZZ was the nearest suitable airport. Dispatch was aware of the decision to divert. Communication with dispatch was limited as flight workload was very high with flight duties; multiple ATC instructions and the traffic congestion.  The turnaround time in ZZZ was longer than necessary because of lack of support from our dispatcher. Initially; our dispatcher told us that we needed to leave behind about 900 pounds of payload; but after looking into it; the first officer and I determined that we had the performance to leave as loaded. I believe we could have shortened the stay in ZZZ considerably if we had received adequate communication from the dispatch support side of the operation. ZZZ station was excellent in responding immediately to all of our needs. In the future; I would like to see ATC issue holding instructions when they are experiencing unusually high traffic volumes; so that we may follow the normal procedures for determining fuel. In summary; this was an ATC induced situation and when our operation became irregular with the diversion; the company system failed to perform adequately; as a result; we had an unnecessarily long stay on the ground in ZZZ.The event occurred because we were planned a release to fly a normal route with normal flight contingencies and we were given abnormal inflight delays in a very busy environment. I would like to see ATC issue holding instructions when abnormally high traffic volumes present in the future; so that we may use normal procedures for determining fuel. 'As long as it takes'; is not a valid EFC (Expected Further Clearance) time. Also; it would be helpful if dispatch was aware of peak arrival traffic times so that they could add appropriate contingency fuel.
EMB135 Captain reports diverting to an alternate airport after extensive vectoring during arrival and ATC being unable to provide an expected landing time.