Worst interview experience.

Round1: discussion with technical lead of card91 on my projects and generic java questions not even worth.
(what could be the possibilities of errors in substr function used for a string).
Got positive response.

Round2: Similar general discussion with technical architect of Card 91. Got to know more about the company and its projects. Got positive response from him.

Round3: Taken by a third party interviewing service(JobTwine).
Question: Given 2 sorted arrays and an integer k, return lowest k sum of pairs, one value taken from each of the arrays. gave her a hashmap solution.
Some generic questions on microservice architecture and java questions. Few questions on MYSQL too. Got positive response.

HR: Didn't even call back after 5 days I called them for update and they tell me it's not the right time to bring me in. She doesn't even have the feedback details with her.

Conclusion: Horrible experience, utter waste of time scheduling and attending interviews.
Company doesn't have a proper interviewing process and structure. Wasted my time any didn't give any offer even after 3 positive responses from all the the rounds.