get onto someone—
1. get in touch with smb., especially by telephone:
- I’ll have to get onto Sarah about the deadline.
2. (coll.) keep nagging or annoy a person:
- She’s been getting onto me for a year to buy her a new coat.
3. (coll.) trace or find a person:
- He tricked people for years until the police got onto him.
get to someone—
1. = get onto someone 1:
- I got to her on the telephone and told her what to do.
2. (coll.) be understood by a person:
- I’ve tried to help the troublesome boy, but I can’t seem to get to him.
3. (coll.) have an effect on smb.’s feelings:
- His sad story really got to me, and I was moved to help him.
4. (U.S. sl.) persuade smb. to do smth., especially by bribing:
- Gangsters can’t operate on a satisfactory scale until they have “got to someone.”