Yes, that sentence can be rephrased for clarity and grammatical accuracy. Here’s a revised version:
"I just received a text from GIG Logistics informing me that my shipment has arrived in Port Harcourt, so I'm heading to their office to pick it up."
### Meaning:
The sentence communicates that the speaker received a notification from GIG Logistics, a logistics company, indicating that their shipment has reached the location of Port Harcourt.