Don’t understand what the OP wants, he’s signed up to this agency and accepted this job and terms (not saying that the agency is or isn’t charging an OT rate and pocketing it, but it does happen), a call late into the shift is never going to be good news for the driver, unless he wants the extra hours.
You had the options to not sign for this agency.
You had the option not to accept this job with its terms.
You had the option not to answer the phone until back at base.
You had the option to do what was asked without throwing your toys out of the pram.
Having been rescued, rescuer and left to sit unaided for hours and still expected to finish the job, it has almost always worked for me long term to do what I’m being paid for, sometimes in cash, sometimes in favours, sometimes in being considered for other (more lucrative jobs) ahead of others with a poor attitude.
You may well have made a few mistakes in this, the biggest one IMO is the last one, walking away before you could potentially get any thanks/ remuneration for helping a fellow driver out of a hole, from hero to zero in one rant.