G.R. No. 167724 - BPI Family Savings Bank, Inc. vs. Vda. de Coscolluela

Respondent Margarita Coscolluela and husband obtained agricultural sugar crop loans from Far East Bank & Trust Co. (later merged with BPI Family Savings Bank) for crop years 1997–1998, evidenced by 67 promissory notes totaling ₱13,592,492.00, treated as a single loan account.
On June 13, 1997, they executed a real estate mortgage over their Bacolod City property (TCT No. T-109329) securing the ₱7,000,000 principal credit accommodation and “those that may hereafter be obtained,” including interest, penalties, and other charges.

Husband Oscar died intestate; respondent failed to pay when due. Final demand on March 10, 1999 sought ₱19,482,168.31.
June 10, 1999: FEBTC petitioned for extrajudicial foreclosure of mortgage for ₱4,687,006.68 (promissory notes 1–33 except nos. 2 and 10).
June 23, 1999: FEBTC (now petitioner) filed collection suit in RTC Makati for ₱12,672,000.31 on the remaining 36 promissory notes (Nos. 34–67 and two earlier notes).

Respondent filed demurrer to evidence, alleging forum shopping, splitting of a single cause of action, and litis pendentia with pending foreclosure petition.
RTC Branch 64 denied the demurrer (Jan. 10, 2002) and likewise denied reconsideration (Feb. 19, 2002), finding each promissory note a distinct contract and petitioner had elected to pursue collection on 36 notes.

Respondent filed Rule 65 certiorari with CA, which granted relief (Sept. 30, 2004), holding foreclosure and collection remedies are alternative, not cumulative, and that filing both splits a single cause of action.
Petitioner’s motion for reconsideration denied (Apr. 6, 2005).
Petitioner elevated the case to the Supreme Court via Rule 45 petition, contesting CA’s grant of certiorari and asserting separate causes of action on each promissory note and limited mortgage coverage.

Was Rule 65 certiorari the proper remedy to assail the RTC’s interlocutory denial of demurrer to evidence?
Did the RTC commit grave abuse of discretion in denying the demurrer by permitting petitioner to split its single cause of action into simultaneous foreclosure and collection suits?