There's nothing to suggest TCS itself have a breach btw.
Basically, if you go for the lowest cost helpdesk - you might want to follow the NCSC advice on authenticating password and MFA token resets.
I've put a 3 part deep dive blog series coming out probably next week called Living-Off-The-Company, which is about how teenagers have realised large orgs have outsourced to MSPs who follow the same format of SOP documentation, use of cloud services etc. Orgs have introduced commonality to surf.