PayPal took my money twice from my paypal credit, and from my debit card. what do i do?

[AngryCustomer21]

I purchased an item from walmart.ca using PayPal credit.

The next day I noticed PayPal also took money from my bank, which was linked to my PayPal account.

My PayPal credit balance is $0 as well.

How can they take my money twice???

Should I file a dispute to my bank, or wait for PayPal first? 

Also, if anybody knows a free PayPal phone number I can call from Canada, please let me know.