Bad service

I am regular client to Spec Savers in Walmer Park PE, however I went for my specs because they were due to be changed. So they assistant Me with friendly as usual but I had to pay for the testing because I am no longer have medical aid as I use so the arrangement was that I will come back towards the month end of October to pay for my balance but unfortunately due to circumstances I couldn't I had to pay for my son hospital bill. Today I am receiving a call from the consultant saying that the manager has given her the instructions that I will be paying normal price due to the fact that I couldn't get my spec's last month. So I will have to pay R1500 more? Just only a month I couldn't pay my spec's then this is a treatment that I am getting, they can loose me as their own client if they are unable to accommodate me. Since 2018 I have been using spec savers and my husband since 2005 but due to the fact this is a treatment I am getting my family and I we are no longer continue to be their client anymore.