Spotting can happen with a bunch of different methods. You do not lose that much blood with spotting, even though it might seem like it[1].
Still not working? You may have more luck on a pill with a slightly higher dose of estrogen, or one that provides estrogen during a different part of your cycle.
Try a different method: IUD

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References:

1. FSRH Faculty of Sexual and Reproductive Healthcare. (Amended 2019). Faculty of Sexual & Reproductive Healthcare Clinical Guidance: Progestogen-only Pills. Retrieved from https://www.fsrh.org/standards-and-guidance/documents/cec-ceu-guidance-pop-mar-2015/