At September 30, 2022, we carried a total debt balance (including accrued interest) of €6,906.8 million, of which €1,561.5 million principal amount is related to the € and USD-denominated Senior Secured Fixed Rate Notes due March 2028 and €3,454.2 million principal amount is owed under our 2020 Amended Senior Credit Facility with maturities ranging from April 2028 through April 2029. Our total debt balance at September 30, 2022 also included a principal amount of €349.9 million related to our vendor financing program, while the remainder primarily represents lease obligations associated with (i) the June 1, 2022 sale of our mobile tower business to DigitalBridge resulting into a 15-year MLA as further detailed above under Financial highlights, (ii) the Interkabel Acquisition prior to the anticipated closing of the NetCo transaction we announced mid-July this year and (iii) other leases. Finally, our total debt balance at September 30, 2022 also included outstanding liabilities of €392.4 million concerning the mobile spectrum licenses following the recent multiband spectrum auction as we have opted for annual deferred payments over the lifetime of each license as opposed to advance payments.
At September 30, 2022, we carried €349.9 million of short-term debt related to our vendor financing program, all of which is maturing within less than twelve months and which carries a margin of 195 basis points over EURIBOR (floored at 0%). This represented increases of €3.9 million versus December 31, 2021 and €18.2 million versus June 30, 2022, respectively, reflecting seasonality in some of our scheduled vendor financing payments and positively impacting our Adjusted Free Cash Flow by the same amount in both periods. For the full year 2022, we continue to anticipate a broadly stable evolution from December 31 2021, as embedded in our FY 2022 Adjusted Free Cash Flow outlook, yet with a certain seasonality in some of our payments from quarter to quarter.
All of our floating interest rate risk and foreign exchange currency risk have been hedged until the maturity of such debt instruments through a series of derivatives, improving the visibility on our future Adjusted Free Cash Flow and minimizing exposure to financial market fluctuations. Excluding short-term liabilities related to our vendor financing program, we face no debt maturities prior to March 2028 with a weighted average maturity of approximately 5.8 years at September 30, 2022. In addition, we also had full access to €555.0 million of undrawn commitments under our revolving credit facilities at September 30, 2022, with certain availabilities up to September 2026.
For more information on our debt instruments and payment schedule at September 30, 2022, we refer to the Q3 2022 Investor & Analyst Toolkit.