If your doctor has made a fast track / 2 week wait referral it is because they are concerned that your symptoms could be caused by a form of cancer. It is really important that you attend any appointment or investigation that is arranged. If you decide you do not want to proceed with any investigations then we would recommend discussing this with your doctor.
You should be seen or investigated within 2 weeks by the hospital team. If you do not hear anything in the timeframe specified on your paperwork then you should phone the number on the paperwork. If you do not have a phone number to chase them up with then contact your surgery to discuss.
Things are a bit different during the COVID-19 pandemic. The document below is worth a read on this subject (can take a bit of time to load).