401k Question

[TrickyBob]

At my last job, I had a 401k through ING.

I quit my job back at the end of May, I had asked the head of HR what happens to my 401k and he said that I should receive information in the mail about closing it out or letting it open; from ING.

I never received anything nor do I know the login information, anymore, for it.

I was a part time employee who made full time hours so I was given a 401k with company match.

It's been a few months now since I quit; what do I do? How do I access the account? (I know through ING retirement plans but the login I had used while I worked there; doesn't work anymore).

Do I request from ING to cash it out? Do I just leave it alone?

I've obviously never had a 401k before, so I've never really dealt with it before.