Why have I been paid by e-cheque?

This is because your customer has not connected their Paypal account with their bank account or card, or their card might have expired. When this happens Paypal will send an e-cheque (rather than immediate payment) which takes 5-7 days to clear. Customers are normally totally unaware of this, so you are best to contact them using the email on their order if you need payment prior to making or posting the item to let them know there will be a delay.