At June 30, 2023, we carried a total debt balance (including accrued interest) of €6,575.9 million, of which €1,455.9 million principal amount is related to the € and USD-denominated Senior Secured Fixed Rate Notes due March 2028 and €3,211.9 million principal amount is owed under our 2023 Amended Senior Credit Facility with maturities ranging from April 2028 through April 2029. Our total debt balance at June 30, 2023 also included outstanding liabilities of €394.6 million related to the mobile spectrum licenses following last year's multiband spectrum auction as we have opted for annual deferred payments over the lifetime of each license as opposed to advance payments. Furthermore, our total debt balance at June 30, 2023 reflected a principal amount of €335.9 million related to our vendor financing program as further detailed below. 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, (ii) the long-term emphyotic lease with Fluvius for the use of its HFC network covering approximately one-third of Flanders prior to the closing of the Wyre transaction on July 1, 2023 as a result of which the lease will be terminated and (iii) other leases.
At June 30, 2023, we carried €335.9 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%). Relative to December 31, 2022, the outstanding short-term vendor financing liabilities declined €10.0 million in H1 2023 with a €14.6 million increase in Q2 2023, reflecting seasonality in some of our scheduled vendor financing payments and impacting our Adjusted Free Cash Flow by the same amount in both periods. We anticipate a broadly stable evolution in 2023 compared to December 31, 2022, as embedded in our FY 2023 Adjusted Free Cash Flow outlook, yet with a certain seasonality in some of our payments from quarter to quarter.
On June 30, 2023, we entered into a supplemental agreement to amend and restate our Senior Credit Facility Agreement (hereafter the “2023 Amended Senior Credit Facility”) to (i) replace LIBOR with CME Term SOFR as administered by CME Group Benchmark Administration Limited as the reference rate for U.S. dollar denominated loans under the 2023 Amended Senior Credit Facility, (ii) bifurcate Revolving Credit Facility I into Revolving Credit Facility A (which has a final maturity date of May 31, 2026) and Revolving Credit Facility B (which has a final maturity date of May 31, 2029) and (iii) increase the total commitments under Revolving Credit Facility B by €90.0 million. Other than the extended tenor, Revolving Credit Facility B has the same characteristics as Revolving Credit Facility A (including (a) a margin of 2.25% over EURIBOR (floored at 0%) and (b) a commitment fee of 40% of the margin) and can be used for the same purposes as Revolving Credit Facility A. As a result of these amendments, we succeeded in extending and upsizing our revolving credit facility commitments under the 2023 Amended Senior Credit Facility and the total amount of our revolving credit facility commitments are now €600.0 million, further strengthening our liquidity profile.
Except for our vendor financing and mobile spectrum commitments, all of our floating interest rate and foreign exchange currency risks 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 5.0 years at June 30, 2023. Our weighted average cost of debt at June 30, 2023, including hedges, was approximately 3.0%, excluding commitment fees, leases, vendor financing and amounts related to mobile spectrum licenses. Finally, we also had full access to €645.0 million of undrawn commitments under our revolving credit facilities at June 30, 2023 as shown in the table below. This represents a net increase of €90.0 million compared to the previous quarter as a result of the upsizing of our revolving credit facility as detailed above.
For more information on our debt instruments and payment schedule at June 30, 2023, we refer to the Q2 2023 Investor & Analyst Toolkit.