Resolver's aim is to make the complaints process as simple and effective as possible.
Some companies (particularly financial institutions) prefer to reply to complaints using the customer details that they have on file. This means that some companies will respond by phone, post, or your personal email address.
Don't worry, any communication is good! If you feel it will benefit your case, you can reply to the company outside of Resolver.
You can then upload copies of these communications to your case file as attachments, or call notes. You'll then have a record of everything saved in your Resolver case file, just in case you need to escalate later.