Why is the ssn needed to proceed?

I found the T mobile terms on their site. They do require information to get credit reports from credit reporting agencies.

https://www.t-mobile.com/responsibility/legal/terms-and-conditions

we here are all user volunteers

I would imagine a SSN is needed for a CREDIT CHECK

The following has a discussion about it, but you may want to contact T-Mobile. https://www.forbes.com/sites/adamtanner/2013/09/25/does-t-mobile-really-need-your-social-security-number/#18a83cd137ae

There was a time when most universities in the USA used the SSN as their employee and student IDs. When I worked at UVa in the 2000’s they were investing huge amounts of personal time in expunging SSNs from all University and Hospital records.

Many State DMV’s used it as your drivers license number too. That was only outlawed in 2004.

The problem with the use of SSNs is that there are restrictions on which government agencies can ask for it and use it, and there are protections for citizens if they don’t wish to divulge it to private companies. State governments enacted their own laws to stop its use as an ID with most state agencies. But there is nothing that prevents any private company from asking for it, and once they have it, they can use it in any way they may think up.

The banks and credit bureaus basically are the ones who engrained it’s use into our banking and credit system. But there was never any reason to have done so other then they could.

I decided some time ago not to give out mine either - I do not have a horror story like yours to tell, but I have never and never will apply for credit, mortgage, or any other type of transaction, so I do not need to have anyone do a credit check. When I first moved here, I found that medical offices were using it as my "account" number and I decided to put an end to that very quickly by contacting everyone (including contacting local, state, and federal legislators and Social Security).

Shortly after I moved to this country and after having established healthcare and wanting to set up an appointment with what was supposed to become my PCP, they wanted my SSN on the patient intake form. I left it blank and the employee said that they must have it for ID and it would become my account number. I was absolutely horrified and told them to delete whatever info they had and left - and then I went to a different provider.

"Official" ???

One of my goals in life is to provide "official" confirmation for your "imagine"s!

You done good on this 'un

Any company running a credit check on you is likely to ask for your SSN. As posted, there is no law in the USA that compels you to provide it to them, and they cannot refuse credit or service if you do not give it to them. They will tell you it is useful to them for their automated credit check software to make sure they check the right person. And that may be true for cases where people have a really commonly used name (how many Smiths do you see in the white pages, for example).

The counter to that though is the credit bureaus do not check the accuracy nor the validity of the SSNs in their files. They don’t even do simple data sanity check such as ensuring their is only a single SSN for any given name and file. At one point some years ago, Experian had 3 SSNs listed under my name in my credit file in their system. I was the one who saw that and I was the one who had to formally request an investigation to fix their error (along with over 20 additional errors in their information about where I had lived, collections for purchases from businesses in States I have never even been to, not one but two spouses I never had, etc).

BTW, this was only with Experian - Equifax and TransUnion (and evening Innovis who yes, I checked) all had accurate data. But they all consider their data proprietary so do not check against each other, even when investigating their own errors.

So many years ago, I froze my credit records (after over a year of constant back and forth with Experian to get everything fixed) with all four agencies, and I don’t give out my SSN to any company asking for it for any reason. You do not have to do so, and they cannot use your refusal to do so against you.

The only time a bank or finance company has the right to insist on it is when you’re personally involved in a transaction of $10K or greater, as they have to report large personal transactions to the IRS (so something like a wire transfer for more than that limit coming into your personal account).