Couldn’t find my transaction
Check the transactions section in you dashboard else contact the technical support.
here is the answer i found in their website : https://www.simplex.com/faq/

Usually, payments are processed within the hour; however, some cases require more attention and can take up to 24 hours to be approved.  You will receive an email once your payment has been reviewed.

If your transaction is still pending, it might be because you have yet to submit to a verification request.
In such cases, an email is sent asking for proof of identity or card ownership – which can land in your spam folder. In case of delays, please check your spam folder for a verification email.