Creditors will stop calling you once you actually file the bankruptcy case. That is the only time they are legally required to cease efforts to collect from you.
However, my office has a special program called the Pre-Bankruptcy Planning Program. In the Pre-Bankruptcy Planning Program my firm is retained to engage in specific planning before you file your case. This planning generally requires that we delay filing the bankruptcy case in order to achieve an important objective, such as: spending down surplus assets to qualify for exemptions; or allowing the deadline to pass to discharge certain tax debts, or for other purposes. During this pre-bankruptcy period, clients refer their creditors to us, and we obtain temporary relief by explaining that we have been retained for bankruptcy. Creditors almost always suspend their collection efforts.