These are survey takers according to the recorded announcement

Robo-call Short survey. Won trip to the Caribbean.  No one to tell STOOOOOOPPPP CALLING ME!

No message left.

Another spam call. Caller ID said Alvarado, Tx.  No message left. Have received a numerous amount of various calls like this over the past several weeks.  Would like to know who sold my phone number to telemarketers.  What happened to the good ole' days when cell phone numbers were private unless you gave the number to a specific person.

Dead air then hung up.