Ask to speak to the office manager and voice your concerns. While I don't believe they will do anything about the staff wearing jeans, which is probably a policy they adopted to make the office a more pleasant place to work and to boost employee morale, you have every right to expect a time frame of some sort as to when you can expect to have your calls returned, and not to be routed to several answering machines/voice mails.
My SIL is an office manager for a urologists office who gets and handles complaints all the time. The funniest one (now) was when she and my brother were soon to be married, and someone called to complain about the "fat bride-to-be" sitting and thumbing through her bridal checklist off to the side and not helping them when the other staff was on the phone. She started crying, she was very Bridezilla and hormonal at the time having just found out she has fibromyalgia, and had to call them back to explain that she 1) was on a break when seen, 2) the break room was having lighting repaired and off-limits for the day, 3) she does not typically deal with patients in the front office but rather the doctors and staff and calls from the patients, and 4) that she knew she was overweight but that her fiance loved her anyway, at which point the person apologized for being rude.
If the office manager doesn't address your concerns adequately then it may be time to switch doctors or at least see if he has another office. Our pediatrician has 2 offices and the staff is wonderful at one and terrible at the other so we only go to the lackluster one in emergencies. BTW, our ped typically calls back the next morning when she gets in the office, around 8:30 am, regardless of what time I called the previous day or what it is regarding. So if it's something I need a faster response to I call the 24-hour nurse advise line at the hospital she's affiliated with❤