DSD Laser no way to contact or call them back

Just had a shocking experience with a parcel today. Someone (two people) was home ALL day to receive the parcel. I was out at meetings and while driving a phone call came in that i missed. I pulled over the side of the road and called back immediately. Just an answering service. DPD laser dont have phones that you can call back on. When I called customer service and said my data could run out could that call me back they said they couldnt call me back as they dont have phones or that service. How are you meant to call them back when you get a missed call. Cape Union Mart. Please don't use this courier. Its frustrating.