Whats link multiple msisdns mean

My phone says that too what does 

Link a MSISDN

ACCESS

Link multiple MSISDNS to single account.

04/08/25

Promotion Enrollment

518******* is eligible for Walmart Smartphone ID250040 due to Device Purchase. Monthly credits in the amount of 2.25 will be applied over 24 months for moto g 5G-2024/357891279748371 mean and for that instance I just got the phone and it says it was being used at a time I wasn't at the store