VisionTek Type C - USB 3.1 Type A Charging Cable not recognized

@tomate_1959  based on your thread title, are you using a cable that has a USB-C connector on one end and a USB-A connector on the other?  If so, then regardless of whether you have a USB-C power bank and you're plugging into a USB-A port on the laptop, or a USB-A power bank that you're plugging into a USB-C port on the laptop, that's not going to work.  In the former case, laptops can't receive power over their USB-A ports; they can only provide power from those ports.  In the latter case, a USB-A port won't support the USB Power Delivery standard that laptops use for charging (since that's only available over USB-C), and USB-A ports also don't support carrying anywhere near enough wattage to run a laptop.  USB-A ports on power banks generally provide 5-15W, with some power banks that support proprietary standards like Qualcomm Quick Charge offering up to 18-24W to devices that support it, but laptops don't.  Laptops are typically designed for 35-240W of power, with many of the "mainstream" models falling in the 45-90W range.  There are very few power banks that can provide that type of wattage -- although Dell makes a few.  If your laptop has a USB-C port (and supports being charged over that port, which not all laptops with USB-C ports do), then look at the Notebook Power Bank Plus PW7018LC, which can provide up to 65W output when used standalone and up to 90W while the power bank itself is connected to wall power.  If your system doesn't have a USB-C port but does have a barrel-style AC adapter connector, look at the Power Companion PW7015L, which has the same output specs.  Those are quite a bit more expensive than most power banks, even those that have similar energy capacities, but again that's because most power banks can't deliver their stored energy at sufficiently high wattage to run a laptop.  Energy capacity is quoted in mAh (milliamp-hours) or Wh (watt-hours), whereas energy delivery rate is typically quoted in W (watts).

If Dell Tech Support told you that a USB-C to USB-A cable would work for this purpose, then I'm sorry but you were given completely incorrect information. Unfortunately that's known to happen.

@tomate_1959  there are definitely uses for a USB-C to USB-A cable.  Some lower power USB-C devices like smartphones, tablets, and even the Oculus Quest VR headset will charge just fine from a USB-A port if its output is on the higher end of the standard output level, i.e. 10-12W, which most USB-A battery packs can provide.  And many (but not all) USB-C devices can be plugged into a laptop's USB-A port and operate just fine.  I realize your laptop already has actual USB-C ports built-in, but as USB-C becomes more commonplace you might find it handy to have a way to connect a USB-C device to a USB-A port if those other ports are already in use, especially since one of your laptop's USB-C ports will generally be occupied by an AC adapter.