Were you going to use the bank statement as proof of residency? If so it has to be a statement that was mailed to you showing your address on the letter or envelope.
This is from their website:
Am I still eligible for OHIP if I temporarily leave Ontario?
You may be out of the province for up to 212 days in any 12-month period and still maintain your Ontario health insurance coverage provided that you continue to make Ontario your primary place of residence.
To maintain eligibility for OHIP coverage you must be an eligible resident of Ontario. This means that you must :
•have an OHIP-eligible citizenship/immigration status; and
•be physically present in Ontario for 153 days in any 12-month period; and
•be physically present in Ontario for at least 153 days of the first 183 days immediately after establishing residency in the province; and
•make your primary place of residence in Ontario.