should i send this signed message to the deposit address or to the address chipmixer gives 1ChipMwvHe5tewb1Uqa9bbZZJDmgPV1TC7? if you can't tell i'm really new to this, so sorry for all the newb questions.
1. Open your Electrum wallet;
2. Go to the Addresses tab (View -> Addresses);
3. Right-click the address you used to send the coins to ChipMixer (sender address) and select "Sign/verify message";
4. It will open a window. Write your message in the "Message" field - something like this:
31 May, 2018. I'm pewpew123 from BitcoinTalk and sent some coins to ChipMixer's address DEPOSIT-ADDRESS-HERE but forgot the session key
5. Click "Sign";
6. Send the data from every field via email to ChipMixer (Message, Address and Signature) along with you explaining your situation;
P.S: If you put even an extra space in the "message" data when sending the email to ChipMixer, the signature will be incorrect. So make sure you send to ChipMixer the exactly same text you wrote in the Message field.