Frankly, do not expect much as for help. The ONLY way is to order a fresh new 7-day and pay for it upfront and then hope+pray that finally, in the end you may get a refund (less fee) for the old pass.

IF you can tell what extra trips you intend to make, it may be worthwhile to check what these would cost as normal bookings- or there may be other alternatives that will not break the bank.

You can read everything about how to make the exchange in the link below. The main thing is that you need to buy the new pass before you can start the exchange process.

https://www.interrail.eu/en/interrail-passes/ordering-info/refund-exchange-policy

Hi Guys, same here: Frist, I bought a 7 days ticket, afterwards I realised a 10 days ticket would bei better. I got the information from the website that exchanging ist possible - after buying the second. I bought this on 19th of April . Until today, I wrought 4 mails and neither did get any useful answer nor an exchange. I submitted a question via the customer Service - 21 days ago I got this message: "Unfortunately we are handling a very great number of requests, and this has slowed us down considerably. If the issue at hand remains, and you have not received a response from us in the meantime through a different thread, please feel free to reach out to us once more through this email with a summary of the problem, and we will do our best to assist you.u Or sincere apologies for this inconvenience once more, we do understand that not receiving a response must have been quite frustrating." Afterwards my request was changed from "Open" to "Solved". 

​​​​​​Do you have any idea to reach any responsible person?

Best regards

@Bianca Pfanner 

Did you request the exchange through your Interrail account?

Dear AnnaB, oh perfekt - for whatever reason, I was initially only ever redirected to Customer Service, but with this input mask it should now at least be officially submitted. Thanks a lot!