Not sure if I'm missing the point, but I have a 3870 which talks happily to my BT cellphone and to my laptop via the BT dongle on the laptop. I can synch with no problems via that route.
I did have to download several updates (the day the 3870 arrived!) before it would work properly. I wasn't best impressed with the quality control on the product, but it works OK now.
What exactly won't it do that you want to?