hi and welcome to GoY.
have you kept them very wet? is there any obvious signs of mould on the plants? Have they been outside or inside? if you can add a photo then we might be able to help you better. sorry for all the questions but sometimes its hard to know straight away without more info.

Probably the dreaded black spot. It spreads from old leaves onto new stems, leaf and flower, and they collapse. Cut it all away, and pray for some new clean growth. Don't worry about feed or anything else. The rule is, before new flowering stems and leaves emerge in spring, cut away all old foliage, however good it appears. Plants in pots are worse affected than those in the ground. Robin White, Blackthorn Nursery in Kilmeston, Hampshire, (now closed, unfortunately), is a national expert. I have always followed his advice.

Hi Seaburngirl and Worthy1

Thank you both for your reply. They were both potted on and placed on a indoor window, only wattered from the bottom when compost felt dry however when i repotted both the roots seamed a bit slimy. The one with no leaves has what I can only describe as a blue/grey fluff on the tip where the growth would have been. Unable to attach photo as not sure how to do so.

I tried to delete this reply and failed so please ignore! hadn't noticed they are plugs.

They need to be outside so maybe the house was too warm for them.The fluff is probably mould and if its on the growing point the outlook is not good. Try to harden the live one off by putting it outside every day for a week or two and bringing it in out of the frost at night. Then plant outside.