Keeps calling but doesn’t leave a message and doesn’t say anything when it is answered

Called 3 times. No response when answered first 2 times blood caked number after 3rd.

Have had numerous calls last few weeks, no message left, hangs up when I answer.

Blocked

they said theyre Change.org OR some other online petition organization, the signal was breaking at times, i can’t remember what they said.
they said the phone call would be recorded for training purposes and such.
they knew this online petition i signed a while ago and asked to confirm my name and then for my address, email address and bank details.
she called to tell me about the petitions on refugees and asked if im able to help with the cause by donating.

i dont know if they’re real or not, i signed alot of online petitions so i cant remember if the one she told me about was what i DID signed a while ago.

my sister told me to hang up because she said that the real deal doesnt call and ask for bank details; they never do.

Repeatedly calls but never leaves a message or speaks when I call back. I've listed as a nuisance call.