If the seller wants to enforce the deadline, they may send a Notice to Buyer to Perform, and then cancel the contract if the buyer still does not remove the contingencies.
The buyer has to provide one, or more, signed Contingency Removal forms. Each one removing, or more, of the contract contingencies. Once the buyer has removed all of them in writing, they may no longer receive a refund of their deposit.
The contingencies are not waived automatically after 17 days. However, elapse of the 17-day period allows the seller to deliver a Notice to Buyer to Perform (NBP) giving the buyer two days to remove contingencies. If the buyer doesn't, the seller may cancel.
The buyer has to provide one, or more, signed Contingency Removal forms. Each one removing, or more, of the contract contingencies. Once the buyer has removed all of them in writing, they may no longer receive a refund of their deposit.