Why Was I Charged $30 For Airfare I Purchased With Skymiles?

I had 25,000+ Skymiles and purchased roundtrip airfare from Atlanta to Dallas (DFW). However, I was charged $30. What is this fee for?

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Fragile And Bulky Baggage tips and restrictions from Delta.com
SkyMiles Fragile & Bulky Items Should you carry it on, check it, or buy it a seat of its own? Find out everything you need to...(45 kg) and 115 total linear inches** (Exception: maximum weight to/from Europe is 70 lbs. [30 kg]) *CAD amount will be charged exit Canada, and EUR amount will be charged exit Europe. For tickets purchased on or before December 12, 2009, fees established by the contract of ...
Requesting Medallion Upgrades
...availability, time before departure, fare class purchased and SkyMiles level. Request a travel companion upgrade ... require payment of a change fee and/or any difference in the applicable fare. There is a Direct Ticketing Charge for tickets purchased from Delta over the telephone, at an airport, or.... Travel agents may impose an additional service charge for ticketing. Upgrades do not affect SkyMiles ...
Requesting Medallion Upgrades
...availability, time before departure, fare class purchased and SkyMiles level. Request a travel companion upgrade ... require payment of a change fee and/or any difference in the applicable fare. There is a Direct Ticketing Charge for tickets purchased from Delta over the telephone, at an airport, or.... Travel agents may impose an additional service charge for ticketing. Upgrades do not affect SkyMiles ...