Your multiple queries ae now coming to some contradicts: -
" About a year ago she had signed on a blank cheque with no date on them."
" I think it was in the capacity of a designated signatory."
" I believe the summons have been issued to both my mother and my uncle as the cheque has their signatures on it "
Further, neither you trying to metion all the facts step by step and clearly, nor you are fully sure about what you are saying; as,
" I am trying to find out about the date of cheque of submission and all those things to see "
Therefore, as per me, First Try to collect all the correct informations, then come to us for correct and helpfull suggestion, otherwise it will be difficult us to guide you also.