did you mix the spray to the correct concentration? That may be a cause.

having said that mine are looking sad due to the dry weather I pruned it back and new growth is showing. So try pruning it and give it a good watering and see what happens.

I'll keep my fingers crossed.

Thanks a lot I will do that

I thin your roses got fungal disease, called "Black Spot" in English. Quite often after prolonging rains or if the rose is situated in a bad place (lot od other plants around, so it cannot dry quickly after rain). Also there are differences between roses in hardiness.
Please, check what you must do on google and look for Black Spot.
Take care: the fungus surivives in the soil, so you must pick all fallen leaves regularly and burn them. However this disease usually kills small roes, bigger sorts usually survive.

Thank you very much