Concerned

Initially, there are various factors and considerations which are pertinent to providing any guidance on your concerns and inquiry.  To the extent that your question does not provide all of the facts and circumstances which may be relevant, please consider this response as a preliminary and general reply.  To the extent that your agreement is in writing and the terms and conditions for re-payment are spelled out, that written document or agreement is controlling.  Thus, if the agreement provides for  a monthly payment in a certain amount at a certain time and you have complied with the terms and conditions, there may be no basis to sue you and attempt to collect.  If there was a sum certain designated, unless the agreement provides otherwise, there would be no legal basis to increase the amount of the agreed to payment amount.  Moreover, unless the written agreement provides for counsel fees, in a "breach of contract:" action, attorneys fees are generally not recoverable.  Also, if the lender is attempting to have you pay off the loan, the provisions of the agreement would also control as to whether and under what circumstances the lender can accelerate the payoff of the loan. If there is no written agreement, the court would most likely look to the routine pattern of payment and the amount of the payment since the loan's origination, how long you have been paying, and over what period of time the lender accepted your monthly payment without complaint - thereby providing some evidence of the understanding between the parties.  I hope that this provides some general guidance.  I would further recommend that you consult with an attorney with respect to the specific facts and circumstances of your loan arrangement who could  then more definitively advise you.