A few days ago I missed a delivery from UPS (in the UK). The next day I got a text from an unrecognised cell phone that just said “Hello” and didn’t respond further. The day after that I got a scam call (another UK cell number) from someone trying to hack into my Amazon account. They wanted me to supply the OTP code that Amazon texts you for 2FA. Anyway I eventually tracked down my package (it was at a convenience store awaiting pick up), and lo and behold they had printed my phone number along with name/address on the package. I suspect someone harvested that and passed it to the scammers (not necessarily a UPS employee, could be the drop off locations they contract with). I suppose I’ll report it to the police in the slim hope that it will help them catch the scammers.
Not sure how you relate your UPS delivery with the scam call? Just because it happened the following day you expected a delivery? I could be just a coincidence.
I'm sure scammer's got get your phone number from many other sources and data breaches.
It could have been a coincidence, but I don’t receive deliveries often, and I don’t get scam calls often, so the timing and circumstances make it highly suspicious.