It should auto pair if both headset and phone are set to auto discover at the same time. It might help if you told us what you are trying to connect width. I was able to connect to a 1st generation Moto-E by following the instructions for both to auto-discover. If there are more than one blue tooth device you may confuse it. Suggest you try it well away from other electronic devices. Reconnecting is a bit slow in my computer room (have seven computers running sometime so I did my pairing in another room. Even so, it takes longer to reconnect in the computer room than in the car for example.
As long as it has bluetooth. (The phone) check the model number of the phone with the model number of the headset and make sure they are compatible. Google should have an answer :)
I'm not sure if the flip phone you're talking about has the particular protocol for this Bluetooth that is something that you would have to look up yourself
Talk to BB customer service. They usually can pull up a copy of the receipt. That said you may have to talk to Jabber about exchange since I thing 60 days is beyond BB's return poilicy.