Hi, I know fishless cycling can seem a pain, my little tank took 8 weeks.
If your ammonia has not dropped at all in 6 weeks (a full 6 weeks, I know some people's 6 week is really just 3
) then the may well be a problem.
Ok, so the ph has been mentioned so have you checked that?
Your ammonia source? It is PURE ammonia right? Doesn't froth up when shaken etc.
Have to ask, water dechlorinator was use....right?
Bump up the temperature to 80-85*
Any chance of getting your hands on some matured media (old gunky filter sponge from someone's filter that is in current use)
It maybe a good idea to let us know the details of your tank and filter type/model as with all posts.
Finally, try to stick with the fishless cycle as getting fish and watching them die is the source of many second-hand tanks for sale on Ebay!