24/7/365 Operational SW Support

In order to fulfill MRO Tender requirement, I would like to know where is possible to find our official time support to any SW issue.

i.e Customer is demanding the following support:

1. Permanent technical assistance (on-call support, 24 hours a day, 365 days a year) for this software, namely at the level of corrections of various types of faults, error repairs, performance rectifications or restoration of service access;
2. Permanent technical assistance (on-call support, 24 hours a day, 365 days a year) for the @ptitude Observer software data communication platform with our system;
3. The carrying out of software upgrades, with the updating of operating systems and applications.