Yes, their line is busy but it is better for you that they provide you with message then they will keep you on hold for 30 minutes and drop your call. Just have patience with them as thousands of people call them for no reason at all and keep their lines busy. I call them periodically for business purpose and sometimes I get that message too but if I try again after few minutes, I will get through.
They are not the most efficient bunch but they do take your calls. Also try different timings. Monday and Fridays are not good days.