Tommer said:
Please let me know what you thing and the best way forward?
It is tricky to advice you Tommer, because your starting point is a non-functional system. Remote diagnosis of component faults is relatively easy, whereas diagnosis of installation faults, where they might be under the floor, is nigh impossible without personal attendance.
If I were a punter in your position, then I'd start getting heavy with the installer.
Start by writing a polite letter, setting out the functional state of the system resulting from his work. Point out that he's been paid, and that you believe that rectifying the problems is his responsibility. Avoid all emotional or emotive words, e.g. "disappointed", "fed up", etc.
Most people will react to a letter like that, but even if he doesn't respond that you've created the basis of litigation in the future, in case you have to pay someone else to sort it out.
Returning to technicalities, if you've shut all other rad valves, and the system is on, and the two rads remain cold, then either there's a blockage in the pipework or the rad valves are not open.