G.R. No. 151908 - Smart Communications, Inc. vs. National Telecommunications Commission

On June 16, 2000, the National Telecommunications Commission (NTC) promulgated Memorandum Circular No. 13-6-2000 regulating telecommunications billing.
Key provisions included:

Subscriber billing statements to be received within 30 days of cycle end, with grace period for late delivery.
No charge for calls diverted to voicemail or recorded messages.
Verification of purchaser identity for prepaid SIM cards; minimum validity of two years; 45-day replenishment grace period.
Announcement of remaining card value before each call.
Reduction of billing unit from one minute to six seconds.

Effectivity: 15 days after publication (June 22, 2000); certain prepaid-card and billing-unit provisions delayed 90 days.
Supplemental memoranda:

August 30, 2000: directives to CMTS operators on stolen units and customer registration.
October 6, 2000: reminder enforcing two-year validity of prepaid packs and six-second billing pulses effective October 7, 2000.

October 20, 2000: Islacom and Piltel filed in RTC Quezon City (Branch 77) Civil Case No. Q-00-42221 seeking nullity of MC 13-6-2000 and October 6 memorandum, with prayer for TRO and preliminary injunction.
Smart Communications and Globe Telecom intervened by leave of court.
October 27, 2000: RTC issued TRO enjoining implementation of the circulars.
November 20, 2000: RTC denied NTC’s motion to dismiss for failure to exhaust administrative remedies, granted preliminary injunction upon posting of P500,000 bond.
February 1, 2001: RTC denied NTC’s motion for reconsideration.

NTC elevated the case to the Court of Appeals via certiorari and prohibition (CA-G.R. SP No. 64274).
October 9, 2001: CA granted the petition, annulled RTC orders, and dismissed the case without prejudice to administrative referral.
January 10, 2002: CA denied motions for reconsideration.
Smart/Piltel (G.R. No. 151908) and Globe/Islacom (G.R. No. 152063) filed separate petitions for review under Rule 45, later consolidated on February 17, 2003.

Does the Regional Trial Court have jurisdiction to entertain the nullity and constitutional challenge to NTC Memorandum Circular No. 13-6-2000 and its implementing memoranda?
Do the doctrines of exhaustion of administrative remedies and primary jurisdiction bar judicial review of a regulation issued under an agency’s quasi-legislative power?
Is Memorandum Circular No. 13-6-2000 (and its October 6, 2000 memorandum) unconstitutional, beyond the NTC’s rule-making authority, or violative of due process and statutory limits?
Have petitioners established a clear and positive right warranting a preliminary injunction against implementation of the circulars?