I think you did the right thing, iPhone. Your mother sounds a bit like my mother. My sister and I are in our 50's, yet my mother still treats us like children. Neither of us have been married, but my sister was in a relationship for 17 years. I think the reason he didn't marry her was because of our mother.
There have been times I've refused to answer the phone when my mother calls for several days. A couple of times I left her house early while visiting her because of her controlling behavior. My sister will call or write saying Mom is upset because she thinks she'll never see me again.
Trying to ascribe guilt to us is their way of controlling us. Hang in there and don't let your mother intimidate or shame you. You know what is best for your emotional health.