What happens if I don’t send back all the inhalers sent to me in a clinical trial?

I’m doing one now from home. I use an inhaler given to me by the company to try out and see now it works for me. They sent me a total of 8, I will likely go through half. They’ve said I sent everything back when I’m done. I just realized I can’t find one of the boxes with two inhalers in it. Will this be a serious thing or does it matter 😭 im paranoid
What happens if I don’t send back all the inhalers sent to me in a clinical trial?
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