Blocked drain caused by drainage rods..
It is not always as simple as screwing the drain rods together and having a "prod"... It can be a lot trickier than that. Firstly you never know what could be causing your drain to block up therefore you do not know what you are "prodding", it could be a number of things such as tree roots, non biodegradable products, a collapsed drain, or, even another service like gas or water (it has happened before now).
The truth is, unless you have x-ray vision (you're very lucky if you do), I suggest you contact Drain Doctor Birmingham and arrange to get an expert on the job!
Here is a video of how to remove some drain rods that caused a blocked drain in Worcester...