3C > 2B shouldn't be used in a blockstring, you're already at a disadvantage from 3C (unless I'm reading that wrong). You can cancel into steins, or special cancel it, but these are pretty unsafe from close up. Her C moves are just unsafe in general especially on IB, so try staggering with 2A, 2B (+1 on block) and ending blockstrings with JC-able moves so you can just get out of there if they're mashing 360 (if they're super mashy, throw out a j2C every now and then - get a nice combo on counter hit that will hopefully discourage them from doing that).
One thing that really helped me with this matchup when I was starting was just staying fullscreen to 5C-range away and just watching what the Tager player does. If they're impatient, they'll probably try super jumping or sledging towards you - 5C/super jump jC to smack them and teach them not to do that. on CH 5C you can go into 6C combo to set up steins. Should be able to 5C his 2D as well, since he's crouching you'll get another free 6C.
When setting up steins : 6D 4D 214D from fullscreen. If he tries to sledge through them, he'll get hit by the 214D. If it's not spaced perfectly, JC the steins, and get ready to:
jC to swat him out of the air if he jumps
land, 5C him if he tries something like sledge or 2D (can do 5C, 214D and move in for a blockstring or set up more orbs)
land, 5D, 4D, 214D to fill up the rest of the bottom of the stage with mines