plasma / back ports/ gpg keyring

[keys84]

Had the plasma issues a few others were having with 15.04
Used the kubuntupa\backports and all was well

Just tried to do an update with muon (stupid I know) as it was telling me I had security issues

Now I have the same issues as before but back ports won't install

Cmd: sudo apt-add-repository ppa:kubuntu-ppa/back ports

Error:
Using tablet so bear with me shortening things slightly

Gpg: keyring 'tmp/securing.gpg' created
Gpg: keyring 'tmp/punting.gpg' created
Gpg: requesting key 8AC93F7A from hop server key server.Ubuntu.com
Gpg: /tmp/tmpylbknva9/trustdb.gpg: trustdb created
Gpg key 8AC93F7A : public key "launchpad kubuntu updates" imported
Gpg: ULTIMATELY NO TRUSTED KEYS FOUND
Gpg: total number processed 1
Gpg: imported 1 (RSA: 1)
OK
Al@n~$

Prease help

[keys84]

found a solution on the googleplex

tried to re-download the keys using

sudo apt-key adv --recv-keys --keyserver  keyserver.ubuntu.com "insert key name here"

that didnt work so did

sudo apt-get clean
sudo mv /var/lib/apt/lists /var/lib/apt/lists.old
sudo mkdir -p /var/lib/apt/lists/partial
sudo apt-get clean
sudo apt-get update

rebooted and am happy all back to how it should be

does this mean i shouldnt be updating with muon updater from now on?
not sure how this will work going forward

[Snowhog]

sudo apt-add-repository ppa:kubuntu-ppa/back ports

This is incorrect. Use: sudo apt-add-repository ppa:kubuntu-ppa/backports