Here are the steps to get this to work (whatever your existing Rule looks like ...):

1. Assume your current rule has some actions (= `SomeRulesActions`).

2. Create a new Rules Component like so:

  - Use parameters related to the user (= say `ParmUser`) and  payment (= say `ParmPayment`).
  - Add the Rules Conditions related to your custom field, which you should have available via the `ParmUser`.
  - Add Rules conditions identical to `SomeRulesActions`, using `ParmUser` and/or `ParmPayment`.
  - QA-test your Rules Component using the "Execute" link in front of it (in the Rues UI).

3. Update your existing rule like so:

  - Delete all Rules Actions corresponding to `SomeRulesActions` (their equivalents are now included in the Rules Component you created in the previous step.
  - Add a Rules Action to execute the Rules Component you created in the previous step.

***Easy, no?***

An alternative solution where you don't need an extra Rules Component, is to rework your Rules logic by using the [Conditional Rules](https://www.drupal.org/project/rules_conditional) module. If you wonder how to do that, use [this link](https://drupal.stackexchange.com/questions/ask).

Ps: I'm assuming this is about D7.