Firstly Im an ATCO (albeit an area bod in TC!) but also a PPL holder. As the latter I'd have done exactly the same as the OP and made an orbit until I could get a word in and clarify what the controller wanted me to do next. That, IMHO, is the safest thing to do in this situation.
Assumptions in ATC are going to be mostly incorrect. 2 scenarios are possible in here...1, the OP continues on after the named fix or 2, the OP orbits until further instructions. Its going to be the case that whatever choice he makes will be the wrong one in the controllers eyes. The issue here is that there was no positive instruction given to the pilot on what to do after reaching the fix. The controller was supposedly busy and did not give further instructions prior to the fix therefore choice no.2 will always default to being the safest one. Ploughing on regardless is never a good idea TBH.
For the controller to berate you was unacceptable!!! He should have given you instructions in a timely manner and, it could be argued, EXPECTED you to orbit. They had absolutely NO cause to give you a hard time. Haggling over the R/T is always a no-no but personally, I would have been sorely tempted to either phone the tower upon arrival or, if possible, arrange to visit the tower to talk the situation through with the ATCO putting your point across.
Spamcan