Dimplex Quantum heaters

I have asked before on this forum and still not had an answer. I have Dimplex Quantum storage heaters which were installed by my local authority after they ripped out gas central heating. Quantum meant to be economical and environmentally beneficial. However, to run just one of them is £25 per week I have 4 in total, but only run one of them. I am over £200 per month. I have two electric panel heaters which are more controllable and cheaper to run. But still over £200 per month for all my electric. I’m on economy 10 which I was told they should run on, but there’s hardly any providers can give this. I’m with OVO, formerly SSE. My next door neighbour still has gas central heating, is on a pre paid meter and is £125 per month for that and electricity. Same size house as mine. She runs her tumble drier umpteen times each week too.