Utilize your financial knowledge, give your answer or opinion to the input question or subject . Answer format is not limited.

How much time does a doctor's office have to collect balance from me?
Seems like the doctor's office is not very organized. Ask for a line itemized bill. You want the date and the specific service(s) performed on those dates. If the bill seems fair and correct, try to negotiate cash discount payment. Ask how much they would settle for if you paid cash. If it is higher than you were thinking, say you were not expecting this sudden bill and if they would accept $xxx. If they say yes, great. If not, try to compromise, pay the suggested offer, or not pay and hope they don't send it to collections.