I've had both good and bad experiences with Joann's. I go there frequently as our choices of fabric stores is amazingly limited for this area. Before they closed the one here in town, it was great. The staff knowledgable or at least willing to to try or go ask someone else. The one that's left in a larger city...it's mixed. Just depends on who's working that shift but most are helpful even if they don't have any fabric/etc knowledge.
Sometimes a tad over-helpful as when my dtr & I were looking at fabric and she asked me "How much is it?" meaning what's the width and a sales clerk busy with another customer a few feet away took the fabric out of her hands without so much as a 'excuse me' and said "It's $9.99 a yard." My dtr said thanks but I was asking Mom how wide this is. Last time we went the person cutting fabric admitted up front she didn't cut fabric, she had been called in due to another's illness. At least she was honest about it.
It seems to me that the selection at our Joann's has become more and more limited - colors, fabrics...just about everything. Writing to the company sounds like a good idea to me - both positive and negative experiences. Maybe it'll help, certainly won't hurt.