yeah your cats will get it eventually, if one gets it the other will follow eventually.

Our first cat didn't like the cat flap and didn't use it very often until we got our second cat and she saw her using it. i think it's a confidence thing, once they see someone else using it ok they get more confident. does take a few weeks sometimes tho. just be very encouraging

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I don't wish to appear to be unsympathetic, but I am, so that's how it comes across.