Stuck ferment suggestions?

[Kershner_Ale]

Long time brewer, have brewed a fair number of high gravity beers and finally had a stuck fermentation on a 1.106 OG Barleywine. I pitched a ton of Cal Ale yeast slurry from a brewery, oxygenated well, set the fermentation chamber at 66 F with a slow rise to 72 F. Mashed at 149 F. It stalled at 1.056.

Any ideas how to get it down into mid-20's on FG? Prefer not to blend with a smaller beer but will if I have to.

 

[Kershner_Ale]

Just checked my other carboy. Same wort, different carboy in different fermentation chamber pitched same yeast slurry. It too stalled at 1.056. I wonder if I got some bad yeast from the brewery?