Bu işlem yapılmadan ödeme alınmamalı.

It turns the verb into a negative adverbial clause meaning without doing:

• yap- → do
• -ıl → passive (yapıl = be done)
• -ma → negation (no doing)
• -dan → ablative (from)
  Combined: yapıl-ma-dan = without it being done.
  This form is often called a negative gerund or negative adverbial clause.

Choose by vowel harmony on the last vowel of the stem:

• Stems with a or ı → -madan
• Stems with e, i, o, ö, u, ü → -meden
  Examples:
• git (i) → gitmeden = without going
• yaz (a) → yazmadan = without writing

The passive highlights the action rather than the actor, which is common in instructions:

• Active: Bu işlem yapmadan ödeme alınmamalı (makes less sense: the process doesn’t do payment)
• Passive: Bu işlem yapılmadan… clearly signals before this process is completed
  If you want a direct command to a person, you could use active imperative:
• Bu işlem yapılmadan ödeme almayın = Don’t collect payment until this process is done

-malı/-meli denotes necessity or obligation (equivalent to should/must). Its negative is formed by inserting -ma before -malı:

• al- = take
• -ın = passive → alın = be taken
• -ma = negation → alınma = not be taken
• -malı = necessity → alınmamalı = should not be taken

In the passive, the original object becomes the subject of the sentence and takes the nominative:

• Active: Ödemeyi alın = Take the payment
• Passive: Ödeme alınır = Payment is taken
  Hence here ödeme remains in nominative.

Replace the negative adverbial clause with -den önce:

• Bu işlem yapılmadan ödeme alınmamalı.
• = Bu işlem yapılmadan önce ödeme alınmamalı.
  Both mean Payment must not be collected before this process is done, though the -madan form is more concise.

Turkish word order is flexible, but placing the subordinate clause Bu işlem yapılmadan first sets the context, making it the topic. You could say:

• Ödeme bu işlem yapılmadan alınmamalı.
  This is still correct, but the original order is more natural for a rule or instruction: condition first, then main clause.