A319 pilot flying reported an integrated drive generator low pressure warning during taxi. After returning to the gate; it was found both IDG reservoirs did not contain the correct fluid.

Narrative

Pushed back from the gate; #1 engine started normal; #2 engine started but we received a IDG LO PRESS ECAM msg. Talked to Maintenance Control and as per their direction attempted another start on the #2 engine with the same ECAM msg. Returned to the gate; met by contract Maintenance; they checked and saw the integrated drive generator (IDG) oil reservoir was very low and upon further inspection noted there was a contaminant in the reservoir that they determined was red colored hydraulic fluid. The First Officer suggested that we check the #1 engine IDG reservoir as well. Out of an abundance of caution I agreed and was shocked when the mechanics reported the reservoir was also contaminated with clearly not IDG OIL but a red hydraulic liquid. Visually checked it myself and took pictures. Discussimg it with Maintenance Control they determined the best course of action was to MEL the IDG on the #2 engine and have mechanics fly in and flush the #1 IDG reservoir on an overnight trip. 'The crew and I returned to the hotel for a XA:00 departure. The following day back on the flight deck reviewing the logbook we saw that MEL X was applied and signed of on the #2 engine. Upon further inspection we found the steps needed to be taken to apply the MEL; none of which were completed. After discussing the egregious mistake with Maintenance Control maintenance operations manager we did a engine run and with contract Maintenance in the flight deck and had them run procedures to manually disconnect the IDG on the #2 engine. Then I had them go out and redo all the steps required by the MEL including rechecking the APU oil level. During the engine run we received a #1 center tank lo press ECAM which I wrote up in the logbook. That write up was balanced by contract Maintenance; at the direction of Maintenance Control; with a reference to A-321 ACT guidance of less than 200 lbs of fuel in the ACT's. I reached out to the maintenance operations manager again and pointed this out; he agreed I re wrote up the ECAM and balanced it using the flight crew placarding procedures. The issue with the #1 IDG was rectified with a flush of the reservoir; changing all the filters and seals; sending the contami liquid from the reservoir for chemical analysis and using a engineering authorization (EA) for a one time revenue flight back to base to finish any required maintenance procedures.Cause: Not sure how such a breakdown of the safety management system can possibly occur at a tenured airline. I'm still shocked that both reservoirs could be serviced with anything other than required IDG oil. Also the issue with having a MEL X on the aircraft as balanced and steps completed all the while none were completed; not even required placards such as MAX ALT 330; is deeply concerning. Add to this the issue with the center fuel pump write up; balanced using guidance from a different aircraft type; glaringly shows problematic issues with current procedures. I can understand minor issues and mistakes but this event is indicative of systemic problems that need to be addressed as soon as possibleincluded a picture I took of the #1 IDG reservoir clearly showing the a deep red liquid; clearly not the required oil.