WLP570 starter issues

I made a quart starter for this vial of WLP570 I bought at the LHBS. 1.040 OG with light DME and a pinch of fermax yeast nutrient. (no, it's not laaglander or whatever) I boiled, cooled, oxygenated, and pitched at about 75F, covered with sanitized aluminum foil, stuck it on my stir plate, and left it for a day. After 24 hours it didn't appear to have done anything - no krausen, and not even any stuck-on crud on the walls which would indicate that there ever was any krausen.

I let it go for a day and a half total, then stuck it in the fridge to flocculate the yeast. I couldn't tell if the yeast volume had really increased much, but I checked the SG of the decanted wort and it was about 1.030 - so it did ferment SOME, but not as much as I would have expected.

I decanted off as much of the wort as I could, made a fresh batch at 1.040 again, cooled and poured it in on top. I let this one run for 2 days, and as before there were no signs of life. I stuck it in the fridge again, and found the SG to be about 1.020.

So, it really seemed like the yeast was dead, but the fact that it's at least fermenting a bit seems to indicate otherwise. I figured after basically making two starters with the yeast, it would "wake up" a bit more but it really didn't.

I figure I am going to give up on this starter - my LHBS isn't exactly top notch, so it wouldn't surprise me if the yeast was pretty abused before I got it. But I wanted to ask first, to make sure I'm not just dealing with some kind of extremely slow-acting yeast without realizing it - the white labs site didn't mention anything like that. So do you think my yeast is probably extremely unhealthy? Or did I probably make some big mistake? And in any case, is there any real hope here or should I not bother trying to save this apparently retarded yeast?

Unless I can manage to salvage this starter, it looks like my belgian blonde is going to get dry yeast and be more of a generic light ale (not that that's the end of the world or anything)...

I recently made a starter with 570, though I did not use a stir plate. I didn't get to monitor its progress but it definitely got going and started dropping out after a couple days. I was going to cold crash and decant however wound up just pitching the whole shebang into my aerated wort. It started fermenting in a reasonable period but active fermentation seems a little longer and slower than expected. It did not have a big krausen surge either.