I keep getting messages that I am running out of storage. I don’t understand why because I buy extra each month

You purchase extra storage for iCloud not storage on your device. It is probably the device which is giving the message.

The only thing you can do is remove unneeded files, photos & apps to increase space on your device.

4twcsc wrote:

Is there a phone number I can call

There is: Contact Apple for support and service - Apple Support

You can also click on the Contact Support link at the top of this page and request a callback from an Apple advisor.