Using Openai to build a client support

My goal is to be able to implement it using the gpt-3.5-turbo intelligence model. Regarding the basic source code of the integration of this model, I did not encounter any problem. I stumble at the integration level for customer support precisely: memorizing conversations, training the AI ​​as an assistant for a specific company, overcoming the openai API token limit problem.
I have another concern about this. How could I overcome the maximum context size length which is 4097 tokens. how do some apps like not have such a context limit?

That is done using embeddings.

Have you considered looking at a platform like CustomGPT that does everything you mentioned?