purchased a new smart TV and will not connect via wifi

[#1]

i purchased a new smart TV and will not connect via wifi , the tv is for my daughters bedroom, it ID's the network but will not connect when password installed i took the TV down stairs and connected via ethernet cable with no problem but still not via dongle which was supplied by. i contacted the TV help line number and they advised me that it was the roiuter blocking the connection , i called plusnet help line and was told to post my problem on here ? can anyone help ?

[#2]

Did you enter the WiFi password/key with all letters in capitals? And if there are any 0s or 1s did you enter them as numbers, not letters? Any letters in the WiFi key can only be in the range A-F.

[#3]

yes inputted all letters in caps as on back of router, all numbers as they are supposed to be, tried hard wire with ethernet cable and connected easily. wirelessly recognises network but would still not connect with correct password, told to contact plusnet by argos help line due to as they informed me the router may be  blocking wifi to router, this has been strongly denied by plusnet and pointed me to this forum , HELP please   

[#4]

Make and ,model?

[#5]

We had a similar problem. The so called helpline of the Tv manufacturer was as much use as a chocolate teapot. The Plusnet guy said that they often get this problem and suggested we got a Powerline adapter (it would have been a real pain to hard wire the TV). I bought the cheapest Powerline adapter I could find and it worked straight away. £19 well spent.
I'm not sure that there is much point in having a smart TV though. We've not really used it after all that faffing about.