My bank is from a country different from where I am applying

hi there I have been worrying over the fact that my bank is Lithuanian and I am already home in Mexico to apply for my visa and have just a letter from the bank stating the amount of my funds, which is the right one and all. I am just worried that they could reject my visa on the grounds of lack of documents? Like if they needed a bank statement for whatever reason, it would be physically impossible for me to get one. It does say on the website that it could be either a stamped letter or a bank statement. I guess I am just nervous about anything going wrong. Has anyone ever had their visa turned down for lack of proof of funds, even though they did hand in either a letter from the bank or a statement, both stamped? Thanks for your help, you will really help someone recover their sleep tonight!!