Spraying for black spot really should be every 7 days to keep control.
Make sure the plant has plenty of room for the air to circulate....trim back any encroaching vegetation.
Pull off any yellowed leaves and dispose of them in the garbage..not the compost. Clean up any fallen leaves immediately once you notice them and dispose of them in the same way.
When you spray, make sure you also spray the trunk and branches of the rose...spores will be on there too.
Try not to wet the foliage when you water.
Place the rose in a shadier spot if possible for a while to give it a rest from the sun's rays. Give it plenty of water and some food....a well fed and well watered plant is much more likely to fight off disease.
In Autumn, when the plant goes dormant, pull off remaining leaves and dispose of them in the garbage. Spray the trunk and branches a final time with a fungicide. In late winter or early spring, before the leaf buds break dormancy, spray the whole plant with dormant oil/lime sulphur spray.
Mulch around the trunk with a nice, clean mulch such as straw or grass clippings to stop any soil splashing onto the plant with rain or watering.
Start your fungicide spraying as soon as the buds break dormancy and continue every 7 to 10 days throughout the growing season.

keep persevearing , it will work out.
I had this trouble with my main climber and nowm we dont have any trouble what so ever