coworker donation ettiquette

When I left work for my cancer treatment, my coworkers all pitched in to help me pay my rent and make ends meet. (they all knew how disability worked...) They ended up collecting 1000 dollars and it was a first in the plant's history!
I promply sent a thank you card to hang up and had my boss update everyone for me.
I was just so frazzled going to all the different surgeons, and specialists, and universities, and dermatology centers, and straightening this and that out, and getting this authorization. Then I had a divorce I was going through...so much going on..and so many finances to juggle. I had no breaks, i was exhausted every day...

well, apparently,some of the people in my particular department were offended that I didn't give them a call personally.They even went as far as to say that they felt jipped...that they were over there working and raising money for me, when I was out here living it up!
Well certainly, every dollar went to paying my rent, for pete's sake.

Was I rude to not call work? I thought it was fine posting a big thank you letter/card and updating them through my boss.... I just felt I was on the phone telling the same story over and over and over all day..do i owe them an apology???