Short payment / inefficient staff

My geyser burst. Instead of replacing the geyser with an electrical one I elected to make up the difference and install a solar geyser (given the current problems our country is facing). I cleared this with Standard Bank in advance of taking any action. They told me that as my geyser was a megaflow that they would pay me approximately R7,800 towards my replacement geyser. This morning I have been paid R5,076.97. No explanation. It has taken a month for them to pay and now they appear to have short paid with no explanation. Every single time that I have phoned Standard Bank I have been met with a different set of requirements to process my claim and now they have short paid. Disappointing - again.