Is it possible to settle debt over phone completely?

Yes, it is possible.
What happens is, you call a debt settlement firm and talk about your financial situation and discuss whether or not debt settlement will be useful to you. Then, the debt counselor reviews your financial situation and decides about a monthly payment that you need to give to the company every month.
This is all you have to do.
And, this thing can happen over phone and wire transfer the amount.

Yes Gary it's completely possible.
With debt settlement, you yourself basically have nothing much to do! The settlement company or agency will contact your creditor and propose the negotiation terms. After the agreement is signed between them, you will be just making the payment to the settlement company, and get done with that debt for good!
The rest is not your headache, as the settlement company will disburse your payment to the creditor.

But after you get the news that the debt is settled, just make sure that it is correctly updated on your credit report.

Yes possible. but make sure the debt relief company is authentic. Check their rating with BBB. Also, read the online reviews before signing for any agreement.

Yeah it's possible. With the help of a genuine debt settlement company you do it online or via phone. You might have to sign the required documents and send them via fax or Email.