How do I find out what size speaker binding I need for the receiver?
You have to take one of the broken ones out and measure it with a caliper, and get the closest. You may well have to do some modifications if you can't obtain the OEM part which with Far Eastern junk is the rule.
I have the strong feeling you are out of your depth on this one.
I really need some decent photographs to get the lie of the land, so to speak, otherwise I can't help you much.
It really is impossible to advise on a major repair of a complex unit I do not have a service manual for and have never seen without pictures. If you can give me good pictures I will know how feasible a repair is short of having the OEM parts or sending it to an authorized service center.
You may have to cut your losses and replace the receiver unfortunately.
This is especially true as you ran the receiver after attempting improper repair, so there is more than an outside chance all the output devices are shot, due to short circuits created by the damaged posts.
It really is easy to take and post pictures, and that is job one, if you want to get a good repair cost effectively.
I will not advise you further without pictures, other wise we are both wasting our time.