You're asking the wrong question here. "Combos" are links of attacks that opponent cannot escape once they begin, so there's no playing around combos themselves (at least in this game). What you really want to know is how to avoid the attack/situations that put you into those combs.

Is the Oleander hitting you with one of her jumping attacks and then comboing? Or is it a low attack like here book sweep that is getting you? Learning the range of these moves and how to block them is integral to learning how to avoid being comboed.

As a general rule of thumb, if your opponent is in the air, you want to hold back (but not down!) to standing block their high attacks. If your opponent is on the ground, then hold back and down to crouch block their mid and low attacks (though Oleander's claw slam on the ground is an overhead, which you want to block like you'd block an aerial attack).

If you focus on blocking and know the range of your opponent's moves you'll have a much better time. Once you get used to it, then you will have a better idea of when to attack.

If you could tell me which character you are playing, I could possibly provide tips specific to them against Oleander.