A photo would be helpful, or at least knowing which varieties of rose. Anyway, you've said they're climbers, and to be frank, they should be in the ground, not in pots. The majority of roses put down long roots and no pot is ever deep enough to allow a rose to do that - climbing roses in particular need to make a deep root system.

Whether its being a pot that's caused the problem now is hard to say without seeing the rose or at least knowing when you bought them and potted them up. Have you inspected them thoroughly for signs of fungal infection, aphid infestation, or any other signs of disease? If not, do that, and add more information if you can to your question.

When you say fresh soil did you mean garden soil or bought potting compost of some kind?

climbing roses make really enormous long roots !!!