Add-on 3x telephoto lenses for Lumix FZ30

[GEORDIEALAN]

I purchased a Panasonic Lumix FZ30 a liitle while ago mainly because I am a relative beginner and wanted an intermediate camera with a wide range lens (up to 12x optical magnification). to me the digital telephoto is irrelevant due to loss of image quality.
In my first flush of enthusiasm I then started buying filters, supplementary lenses and other "necessary" items off e-Bay, and in nearly all cases was pleased with the additional effects.
However having purchased a wide angle add-on lens from a supplier in Hong Kong , with which I was pleased, I then made a subsequent purchase of an add-on 3X High Definition telephoto lens from the same supplier, who incidentally advertised it as suitable for the FZ30, and I was extremely disappointed with the results.
I am attaching a few shots --with and without the 3x lens ----to show the terrible aberration and colour fringing obtained with this lens, rendering only the central 10% approx of the picture in focus. After sending the pics to the supplier for advice they agreed there was a problem and the lens was returned and a full refund given.
I then considered an alternative supplier based in America who was advertising similar add-on lenses of different manufacture and asked for reassurance that their lens would perform satisfactorily, and sent them copies of the attched pics.They commented that they felt they may not be able to meet my "high standards" (surely they can't be serious?) and suggested a 2x lens may be more suitable for me.
Firstly ---am I doing something wrong?
Secondly--are my standards too high in rejecting this lens (see pics)?
Thirdly --is there a suitable 3x add-on lens available (at a reasonable price) that works with the FZ30?
Fourthly- why are these people continuing to advertise lenses that do not appear to work satisfactorily?
Any help in this direction would be appreciated?