Perhaps with those speeds you should downgrade the package to the 4mb service so at least you are not being over charged. We live in Uzumlu and this is our second location within the village and have to say we have had over 5mb service at both ends of the village (currently receive just under 7mb) so sounds like we are very lucky compared. Do you use the internet via ethernet or wifi, it may be worth doing a speed check on both connections as wifi speed especially may be interferred with by a 3rd source like cordless telephones or house alarm or structure.We literally lose our connection from one end of the house to the other so being nearer the wifi/modem is essential also to get the speeds we do, the dropping of signal sounds like this may be the cause? Also have TTNet sent an engineer out to test the line, if not insist they do/ also a personal visit to their offices may pay dividends as they have a engineer dept which are more understanding than the operators and on a number of occassions they can improve the line just by pressing some buttons their end, unfortunatley the operators at TTNet are still not fully used to the new system they had installed early last year. Uzumlu also has some fibre optic lines feed so there is no excuse for them not to be able to sort out the issue, poor operators will just respond and state you are still getting the upto 8mb service even at p*ss poor speeds which is a cop out. As said test both speeds and if it is poor on ethernet also, I recommend to try the personal visit route first.
Just as a after thought going with another internet company is not a solution really as they use the same lines as TTnet usually just a different billing company at the ned of the day?