Is there a way to cancel transactions and withdraw the funds?
Unfortunately, not Which is why be extra attentive when generating any type of a transcation on Blockchain.
This is one the reason crypto is not that popular. Lots of people use it for bad reasons
and, say, the forgers use it as well.
It is about user that how he wants to use it and how he moves with bitcoin or any other crypto currency, before investing in crypto currency it is very important to know how can we use it and how can we get profit from it, try to buy low but then hold, using it not good according to me but if somebody want to use it is really reliable way to buy anything.