Bangladesh weak against pace, bad against spin, what to play?

Bangladesh conceded a 220-run defeat in Durban followed by succumbed to hosts South Africa by 332 runs in Port Elizabeth.
They were wrapped up on 53 in the 2nd innings of the first Test and the two South African spinners Khashav Maharaj and Simon Harmer shared all 10 wickets between them. Maharaj notched seven and harmer claimed the rest. The whirlwind duo repeated their performances in the 2nd innings of the following match as Bangladesh continued their sorry figure to be bowled out on 80. The two turner seized 29 off Bangladesh's 40 wickets in the series.
After massive defeat in the last match, Bangladesh Test skipper Mominul Haque claimed that they are not well enough against quality spin.
"We can't play quality spin well," Mominul said during post-match press conference on Monday. "None of us but one or two can play spin."
But it is an established truth that the subcontinent players are very good against spin and they had to do extra home work against fast bowlers especially during away series. They are heard to speak about extra efforts to cope with grassy wickets.
Before any tour out of sub-continent, Bangladesh think tank and players show their special concentration on fast and bouncy tracks.
Besides, many a cricket whiz blames our wickets and infrastructure for player's weakness against pace. Things are years old problem here.
Mominul's recent statement therefore, should be considered as a major area of concern as well as a threat to Bangladesh's cricket. He said, "We possibly don't understand what to play in which area against spin."
If things like that which type of balls they are capable to play?
Under Mominul's captaincy, Bangladesh Test team hardly could bring anything satisfactory except the Mount Maunganui triumph few months back. It is better to term 'accident' in place of the word 'triumph'.  
It is not necessary to go far as during this tour, Bangladesh ODI team scored 300 plus runs against even stronger South African bowling attack combining Kagiso Rabada and Lungi Ngidi alongside Maharaj and Harmer and sealed the title 2-1. If the one-day team could play, then why the Test team failed to score even 100 runs in two occasions.
Blaming to 'quality spin' therefore, is a very lame excuse from Mominul.