How do I solve this problem in seasplot?

Making this code:

library(BETS)
library(TStools)
selic <- BETS.get(4189, from = '2000/01/01', 
                   to= '2016/02/01',freq=12)
seasplot(selic,outplot = 3,trend = F)

Give this result

Error in if (diff(range(colSums(ynt))) <= .Machine$double.eps^0.5) { : 
  missing value where TRUE/FALSE needed

If you do not have missing values from January through January, it works. How do I get the missing values and run?