Contact the IRS to see if your return has been filed. If you can, try to obtain information on your CPA prior to calling, like the PTIN, CAF (if any), CPA number, etc. It may be in other documents you've gotten from the CPA - particularly previously filed IRS documents. The IRS has a process and form for complaints against CPAs and preparers.
I would be careful not to do much against the CPA until your taxes are filed, either by this CPA or by another CPA (or preparer or by yourself). If you're resolved to go somewhere else now, then pull that trigger and don't pay the CPA's bills until the full amount due is negotiated (presumably down to zero due).
You can ask for forgiveness from late penalties if you can show "reasonable cause" for the lateness. You can also freeze any interest from accruing by estimating and paying your taxes now through eftps.
If the CPA has not told you an amount due, then there's good reason to believe the return was not filed. However, if you had some arrangement or prior discussion of the amount due, then it may be possible that he submitted your taxes and attached a bank account payment number (did you provide him one?).
You really need to get in contact with the CPA to understand what's been done, if anything. Try contacting other people in the enterprise, if there are any. If you know other clients of the CPA, contact them. If you were referred by friends or family, use them. If you know where the office is, try going down there (be direct but never aggressive).
Remember to file a complaint with the IRS for "preparer misconduct" on Form 14157. You can file compaints with the state board of accountancy or other responsible licensing agency (e.g. CA, TX, NY). I believe Form 843 is the appropriate form to request abatement of the late penalties (with brief explanatory attachment), but you can review the instructions and let your next CPA consider it.