Paypal has no right to withdraw out of the bank account after the deposit is made, especially after 10 days.
Paypal User Agreement, section 10.2.d:
We may reverse a payment (including, if appropriate, to the sender’s Funding Source), that violates our Acceptable Use Policy or section 9, or which we reasonably suspect of violating our Acceptable Use Policy or section 9;
You agreed to it, whether you read it first or not.
And selling Bitcoins would probably be taken to fall under either: (Paypal Acceptable Use Policy)
relate to transactions that (a) show the personal information of third parties in violation of applicable law, (b) support pyramid or ponzi schemes, matrix programs, other "get rich quick" schemes or certain multi-level marketing programs, (c) are associated with purchases of annuities or lottery contracts, lay-away systems, off-shore banking or transactions to finance or refinance debts funded by a credit card, (d) are for the sale of certain items before the seller has control or possession of the item, (e) are by payment processors to collect payments on behalf of merchants, (f) are associated with the sale of traveler’s cheques or money orders, (h) involve currency exchanges or cheque cashing businesses, or (i) involve certain credit repair, debt settlement services, credit transactions or insurance activities.
or
Airlines and scheduled or non-scheduled charters/jets/air taxi operators; collecting donations as a charity or non-profit organization; dealing in jewels, precious metals and stones; acting as a money transmitter or selling stored value cards; selling stocks, bonds, securities, options, futures (forex) or an investment interest in any entity or property; or providing escrow services.