The models of retrial queues M/M/K/K with delayed feedback are considered. If upon arrival of primary call (p-call) there are free channels then it occupies one of them for a some exponentially distributed time; otherwise, it in accordance to Bernoulli scheme either leaves the system forever or go to orbit for retrial calls (r-calls). After the customer is served completely, it will decide based on Bernoulli scheme either to join the orbit for re-service after some delay (delayed feedback) or to leave the system forever. If upon arrival r-call there is a free server, then the arriving call begins to be served immediately; otherwise, it in accordance to Bernoulli scheme either leaves the orbit or return to orbit. An approximate method to calculation of the steady-state probabilities of the appropriate two-dimensional Markov chain as well as performance measures of the system is developed. Results of numerical experiments are demonstrated.