I was registered to donate blood in 2 regions, one where my university is located and one in my hometown. I received at least one phone call per week from them. The near harassment has almost lead me to regret giving blood. I've started blocking their numbers, but it looks like they are getting new ones.

Go to the Red Cross website, log into your account (or create an account) and change the permissions line so they know to not call you  Since you are registered in 2 regions you may have to make accounts in both to make the change in both.

I'm a regular donor.  I've given about 120 pints.  I had to ask them to stop calling when they called my cell during a tornado warning while I was trying to herd my cats into the tornado shelter.

Red Cross begging for blood

They call at a min. of two times a day. Every. Single. Day. Good luck asking them to stop and good luck with blocking all one million phone line numbers

American Red Cross. Called me 12 times in successive days. Though I do have a rare blood type I also give regularly. I downloaded True caller from the app store just for them! They will hit you with a 1-800 number as well as local calling prefixes. Impossible to stop unless you get some sort of spam blocking utility. I will never stop giving blood but the calling is borderline harassment