Unhappy about my Hospital claim

i submitted 3 hospital claims for 3 different hospitals. the two claims were paid the week of 25 February 2019 but the one claim is still outstanding and i have followed up with them a number of times and they told me that its still with the claims department after 2 weeks of submission, this is not fare as they keep on telling me about different references but no one is actually helping me, i am really disappointed in them and even thinking of cancelling my policy with them. i would appreciate it if their Head office would take my complain seriously and help resolve it.