Insurance /plumbers overpricing

My 85 yr old mother has been a client of Integrisure for over 10 years. Wednesday her geyser valve started leaking copiously. Contacted Integrisure who sent out one of there "approved" plumbers who quoted R2200 of which the insurance would only payout for 1 hour of his labor - also this plumber did not have the part but would have to source/order part, and would get back to us - still have not heard from this plumber - so contacted another plumber who sourced the part within half an hour and is prepared to the job for R1400. As there is no financial gain to using Insurer's plumber we requested them to use the other competent plumber who can get the job done immediately and at almost half the price.

They would not allow this. My complaint is why do their "approved" plumbers charge nearly double - resulting in no gain to the insurer's clients who would still have to pay out of their own pocket more or less R1000. Also it could be noted that the monthly premiums paid to Integrisure are over R1000. Are we being "****med?"