I later came back the same day to redeem the remaining voucher but I got a response that the voucher is invalid or already redeemed.
I have sent emails to the team and it has been 48 hours but I have not received any response from the team.
If you're so worried that you might make a mistake or get even more nervous then wait for a response from chipmixer, they should reply within another 48 hours and vouchers don't expire.
Do you know the session token for when you made the 1btc voucher from chipmixer? Are you able to redeem that session, skip to step 3 (I think) where your voucher code is presented and copy and paste the voucher into a new chip mixer session?
Do you know how you originally managed to save the voucher, did you use copy and paste or did you write/type it down? That could've caused the discrepancy.
As a final point, don't store more on a fully online wallet than you'll be able to ignore losing. If you're dealing with 1btc and it feels a lot, break it down into 10, then if that still feels a lot, half it still until you get a comfortable size. Fees a low at the moment but even if they weren't, it's not worth the worry of losing a large chunk of funds.