A very similar event happened to me in the beginning of this year, involving the USPS (rather than the UPS). Actually, it was on the 5th of January, come to think of it. Instead of clicking on the link in the SMS, I visited the page on my computer. The page was obviously made to impersonate the USPS website, except the link led to a tracking page with a populated shipment number.

The domain is/was uspexlocrts.info and at the time, a whois lookup showed that it had been registered just a few hours before I received the SMS on my phone. There was a subsequent modification about a month later.

The whois information is largely redacted, with only the state/province and country field showing up as Beijing, CN.

I ended up submitting all the information via the (authentic) usps customer inquiry interface and basically asked them to deal with it however they saw fit.

A few days later, when I tried visiting the page again, I noticed that the site had been added to Chrome as a potential phishing site (attempting to visit the site first shows the all-red Chrome warning page instead).

Finally, on the 15th of March, I received a response from the USPS:

-- Dear <Customer>,

Thank you for contacting the USPS® Internet Customer Care Center.

"Smishing", a form of phishing, is an unsolicited SMS (text) message. Victims will typically receive a deceptive text message that is intended to lure the recipient into providing their personal or financial information. These scams often attempt to impersonate a government agency, bank, or other company to lend legitimacy to their claims. Common lures include “your account has been suspended,” “there is suspicious activity on your account”, "there is a problem with your shipping address" and “there is a package waiting for you at the Post Office.” To report USPS-related smishing: Please visit the United States Postal Inspection Service ® smishing page at https://www.uspis.gov/news/scam-article/smishing/ for additional information and reporting steps.

If you have any additional questions or concerns, please contact us again.

Thank you for emailing your Postal Service™,

USPS Internet Customer Care Center