A new fee Verizon plans to impose on its business customers has galvanized educators this week to rally around the school messaging service Remind—so much so that the telecoms company agreed to make an exception and waive the impending fee for Remind’s K-12 users. But the surcharge, set to go into effect on Feb. 1, will be passed on to at least a dozen education companies—not just the one getting all the attention. Here’s some background: Verizon has built a…