>You need to stay on top of things and communicate regularly, even if your client doesn't.
you have to tell them that they have to communicate regularly too. otherwise, how can business be done. how can issues be sorted out. they will blame you for the issues later, although they did not discuss them with you. aka cya syndrome.
if they continue not to do it, you should fire them. or use reverse signoff protocol.
"we mutually agreed at the start of this engagement, that if you don't sign off on acceptance of a given deliverable within x days, it is understood that you have accepted it and will pay for it".
If it happens more than once, leave them. it indicates they don't take you seriously.
all such terms should be put in the contract, initially.
if they don't agree to such mutually protective terms, don't sign the contract at all.
Negotiate a kill fee for the contract too.
Been there, seen that, got the t-shirt (and the scars), for many of the above points.
The kill fee idea, I got from this video:
"fuck you, pay me" by mike monteiro
https://youtu.be/jVkLVRt6c1U