These are 3 pain points related to the setup of your interconnections but you also have an overhead cost when it comes to running these interconnections.
First, you have the complexity of the invoicing which is multiplied by the amount of different Service providers you work with and which has a cost between your team and your Finance department when it comes to the monthly reconciliation of invoices.
Then, there is all the time that you lose with the 1st line support of your providers every time you need to report an incident and have to wait for someone with the sufficient technical skills and accesses to look into it.
Finally, there is a cost that hides inside a process that should be positive for you but could turn into the opposite: the contract renewal. When the commitment term on you circuit reaches a certain date you are entitled to renegotiate and bandwidth prices tend to decrease over time. But while this could sound like something positive for you if you don't forget about it (If you don't ask, you won't get!); this often comes with an updated legal document which leads to a renegotiation of terms and a huge Legal cost on your end.