Hello!
The different pieces of contact information are all potential ways to get in touch with the Internet number resource holder. If you have difficulties reaching them via any of those details, you can report this to us. I would recommend making a reasonable attempt to contact them first though, for example by giving them a phone call if you find that their email addresses are no longer working.
My experience: I've used the form because the email contacts from a provider in Romania were invalid. The phone contact given in the RIPE database was only a mobile phone number in Romania. I searched for this number in the web and only get a few results which all directed to the entry in the RIPE database. So it seems that this (prepaid?) phone was only used to register this IP space with RIPE. My claim was denied because I didn't made an attempt to contact the provider on mobile phone in Romania. I didn't contact them because I don't speak Romanian and I feared retaliation from possible criminals in Romania. So for an individual it may be very difficult to fulfill all the external requirements which are made by RIPE NCC. And, of course, RIPE may be in a better position to repel retaliations. RIPE NCC wrote back that they don't have the staff to check if the entries in the database are correct. So if RIPE will guarantee the validity of the database today they seem not to have the personal capacity for research. Best regards, - Karl-Josef Ziegler