You would perhaps need to post a photo. Cymbidiums are usually pretty well behaved. If mature and given a cold spell thru Autumn and bought indoors, they should be starting to flower from now until Feb.
Cyms need a colder spell compared to other orchids. We have many in our unheated garden room and they are sending up flower spikes now, the second flowering.
They do though still need humidity and rain water when needed. Spraying helps to keep the humidity up.
Have you repotted them? They are better pot bound.
They are prone to a virus, which fits your description. Sorry but you should discard them. If they don't flower before Christmas, as a rule they are not going to.
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but no flower spikes.
Thank you for your reply.