Thanks for sharing. Nice to see you back.

Hi.

Long time no see. How have you been doing?

Maybe either way is correct? See the usage of its negative form below:

used to

Adjective

accustomed to: I am used to being a medical guinea pig

Verb

used as an auxiliary to express habitual or accustomed actions or states taking place in the past but not continuing to be the case in the present: he used to vanish into his studio for days


USAGE/b>: The most common negative form of used to is didn't used to (or didn't use to), but in formal contexts used not to is preferred.


URL: http://www.thefreedictionary.com/used+to