I personally use the book you mentioned, and have had great success using that method of evocation. I have found it to be both safe and reliable, so it seems that the source of your problem is not your methods of choice. Do you think you may have been lusting for result? Do you think you picked the right demon(s) for the job?
Also, are you certain that someone else was magickally attacking you? This is much less likely than you may think, but if you are certain that they were then how did you respond? If you responded to a curse with a curse, then I would not be surprised if they responded to yours in-kind.
If you just want to get on with your life, I would suggest using the protection rituals mentioned before, and then calling on the demons to bring you new opportunities and to work towards increased prosperity (or whatever it is you’d like to work towards). If you don’t attack them back, they will likely lose interest in you and move on as well.
I suppose you could seek revenge if you really want to, but I think there is great wisdom in the words, “The best revenge is living well.” Do what you will, but I find that ignoring an enemy while enjoying my life is often just as effective at destroying someone as an actual curse. Let them be consumed by their own hatred, while you laugh all the way to the bank.
Of course, if someone is actively working against you then a small amount of magickal work may be needed, but if someone is really out to get you, it should be simple enough to use their own energy against them. Put up a binding and a silencing ritual to prevent any real damage, and follow-up with one to expose and amplify their greatest weaknesses.
From there, all you have to do is watch the fireworks as their true nature is exposed, and they bring about their own downfall. You can get on with your life, knowing that you will not come to any real harm, and that their efforts against you will only bring harm to themselves. Why waste your time on small people, when you could be bettering yourself or bringing joy to those around you?
I’d check out Koetting’s recent video on being a “marked man” as well. I drew some inspiration from that video, and it is definitely one of his that just makes me feel like going “HELL YEAH”