Ok, I will answer my own question so that others do not fall into the same problem. @DarkDust was actually correct. there was a tiny line which I was completely ignoring:
**retriesNumber++;**
It looks like an innocent sentence, but because retriesNumber is a member of the class, it is actually meaning
(INVISIBLE strong pointer to self)->retriesNumber
so the solution was to declare it as a property (versus a member ivar) so that we can use self to access it, and then write:
pSelf->retriesNumber++;
Thank you guys for your quick support, and I hope others will learn from it too!