You know I never use a reseller just the corporate stores. However if you upgraded at verizon stores and took any sort of subsidy for those new devices, you lose the unlimited. If you paid full price for the new devices you would have needed a data plan is as much you did not know this or maybe not read that verizon was doing away with unlimited if you did not pay full price. it was all over the net and the news.
You say you had unlimited, however unless it was totally explained to you about the ways to lose it I would say that reseller was either devious, or simply uninformed. What ever reason you believe is totally up to you.
You could write a stinging letter via US Postal Service with return receipt requested to verizon corporate the address should be at their web site http://www.verizonwireless.com under "Contact Us"