Pre Payment Meter Opening Readings

Hi, I switched to Bulb with a pre payment meter already in the property. Unfortunately, I didn’t think to take the meter readings when my supplier switched, I thought it would happen once I used the key Bulb sent me. Now I’m being billed for a lot of money for the 3 weeks between moving in and switching to Bulb. I have the readings from when I moved in and I have readings now but I don’t have any readings from when Bulb took over. Is there any way to get these? I assume they were sent electronically by Bulb but I might be wrong. Anyone?