Such coverage may be written on a actual basis of current value per unit, but in no case less than $20, (c) The User agrees to maintain, for the term of this Agreement, the loss of freight insurance coverage for loss of and damage to the bill of lading contained in the Equipment while in the custody, retention and/or control of the User. Such coverage is equal to the minimum amount of $250, (d) All insurance certificates must give the carrier a cancellation period of at least thirty (30) days. 8. Fees. The user undertakes to pay the carrier`s fees set out in Appendix “A” for each day or part thereof. The network operator shall charge the user those charges monthly. The user must forward the billing disputes to the carrier within thirty (30) days from the date of the invoice.