I have a Panasonic land line phone and I used up all of the memory for blocking numbers, and we still get spam calls. I don't answer our land line anymore, but the telemarketers keep trying.

If someone calls me on my cell phone and doesn't leave a message, I put them on block. I haven't reached the limit on blocking numbers on my cell phone. I suppose I could change our land line to a voice mailbox or cell phone.

Credit card companies and some companies that deal with you require a phone number, but I assume they are the ones selling my information. I even think the cell phone companies and some cell phone companies are involved as well. I think you need a voice mailbox for those you deal with and a private line for work, friends and family.