MX = Part 145
CAM = Part M
Fossy is spot on. Your CAMO is responsible for controlling the mods on your aircraft, and they should consult the operator on when to embody them (which becomes a Part 145 function once scheduled). Depending on the contract you have one company can perform both functions (if appropriately approved) or it can be separate companies. In some cases (such as AOC) the operator himself may be the CAMO and responsible for scheduling mods.
Some SBs are optional and the operator can opt not to take them up. Mandatory ones should be done and the CAMO will normally schedule these in a suitable MX slot. However they do not have a legal status, that is what ADs are for, and ADs will always have a set compliance date. You do not have any choice over these; they must be done and by the time stated, even if it means grounding the aircraft (because it would be illegal to fly outside compliance).
Incidentally if you are on a N, VP or M registration, EASA Part M/Part 145 rules do not apply, however SB/AD embodiment rules are the same. I wouldn't expect an aircraft to be held for a mandatory SB, but that's without knowing the circumstances and there may have been reasons.
Unless your contract provides for damages (and few will cover consequential losses, loss of business etc) you may be better off asking nicely for an explanation of what happened and angling for concessions, rather than demanding compensation.