I would like to say that I think too many of us put all our eggs in one basket, especially when we have some major need and depend solely on a spirit to manifest the need.
First, there’s a reason that in Golden Dawn the Portal (evocation) Grade is last, after the the Neophyte and Elemental Grades. Learning to communicate effectively with spirits is a challenge, and if you have made a pact in the blind without having heard the spirit agree to the terms, you can be left high and dry.
Second, spirits can actually fail at a task. They can accomplish great feats, but there are things they can’t (or won’t) do.
Finally, this is why self-development is so important. I know you’re not here for a lecture, but I want to help you. Learn to cast your own spells, harness the natural energies of the cosmos, create chaos sigils, mix herbs and oils, charge candles, etc. When you combine all that knowledge into a super ritual or short series of rituals, to include a petition and/or offering to a spirit, you have put enough force out there to manifest almost anything. And it doesn’t take long to learn these things. You’ll just have to put it into practice.